diff --git a/src/main/kotlin/com/moa/entity/DailyEventType.kt b/src/main/kotlin/com/moa/entity/DailyEventType.kt
index 897acdb..ce70312 100644
--- a/src/main/kotlin/com/moa/entity/DailyEventType.kt
+++ b/src/main/kotlin/com/moa/entity/DailyEventType.kt
@@ -1,6 +1,32 @@
 package com.moa.entity
 
+import java.time.LocalDate
+
+/**
+ * 일자별로 표시할 부가 이벤트를 정의하는 열거형입니다.
+ */
 enum class DailyEventType {
-    PAYDAY,
-    HOLIDAY,
+    /** 급여일에 해당하는 경우 */
+    PAYDAY;
+
+    companion object {
+        /**
+         * 특정 일자와 급여일 설정을 바탕으로 해당 일자에 표시할 이벤트를 판정합니다.
+         *
+         * 현재는 급여일([PAYDAY])만 지원하며, 추후 공휴일 등 다른 이벤트가 추가될 수 있습니다.
+         *
+         * @param date 이벤트를 판정할 기준 일자
+         * @param paydayDay 사용자 설정 급여일
+         * @return 해당 일자에 적용되는 [DailyEventType] 목록
+         */
+        fun resolve(date: LocalDate, paydayDay: PaydayDay): List<DailyEventType> {
+            val events = mutableListOf<DailyEventType>()
+
+            if (paydayDay.isPayday(date)) {
+                events += PAYDAY
+            }
+
+            return events
+        }
+    }
 }
diff --git a/src/main/kotlin/com/moa/entity/DailyWorkStatusType.kt b/src/main/kotlin/com/moa/entity/DailyWorkStatusType.kt
index ea20144..1a59a51 100644
--- a/src/main/kotlin/com/moa/entity/DailyWorkStatusType.kt
+++ b/src/main/kotlin/com/moa/entity/DailyWorkStatusType.kt
@@ -1,7 +1,55 @@
 package com.moa.entity
 
+import java.time.LocalDate
+import java.time.LocalDateTime
+import java.time.LocalTime
+
+/**
+ * 일자별 근무 진행 상태를 정의하는 열거형입니다.
+ */
 enum class DailyWorkStatusType {
+    /** 근무 일정이 없거나 상태를 판정할 수 없는 경우 */
     NONE,
+
+    /** 아직 근무 종료 시각이 지나지 않은 경우 */
     SCHEDULED,
-    COMPLETED,
+
+    /** 근무 종료 시각이 지나 완료된 경우 */
+    COMPLETED;
+
+    companion object {
+        /**
+         * 특정 일자의 근무 스케줄 정보를 바탕으로 근무 상태를 판정합니다.
+         *
+         * 근무 유형이 [DailyWorkScheduleType.NONE]이거나, 출근/퇴근 시간 중 하나라도 없으면
+         * 상태를 판정할 수 없으므로 [NONE]을 반환합니다.
+         * 퇴근 시간이 출근 시간보다 이른 경우에는 자정을 넘기는 근무로 간주하여 익일 종료 시각 기준으로 계산합니다.
+         *
+         * @param date 근무 상태를 판정할 기준 일자
+         * @param scheduleType 해당 일자의 근무 일정 유형
+         * @param clockIn 출근 시간
+         * @param clockOut 퇴근 시간
+         * @param now 상태 판정에 사용할 현재 시각. 기본값은 [LocalDateTime.now] 입니다.
+         * @return 판정된 [DailyWorkStatusType]. 종료 시각 이전이면 [SCHEDULED], 이후면 [COMPLETED]를 반환합니다.
+         */
+        fun resolve(
+            date: LocalDate,
+            scheduleType: DailyWorkScheduleType,
+            clockIn: LocalTime?,
+            clockOut: LocalTime?,
+            now: LocalDateTime = LocalDateTime.now(),
+        ): DailyWorkStatusType {
+            if (scheduleType == DailyWorkScheduleType.NONE) return NONE
+
+            val resolvedClockIn = clockIn ?: return NONE
+            val resolvedClockOut = clockOut ?: return NONE
+            val endAt = if (!resolvedClockOut.isBefore(resolvedClockIn)) {
+                date.atTime(resolvedClockOut)
+            } else {
+                date.plusDays(1).atTime(resolvedClockOut)
+            }
+
+            return if (now.isBefore(endAt)) SCHEDULED else COMPLETED
+        }
+    }
 }
diff --git a/src/main/kotlin/com/moa/entity/PaydayDay.kt b/src/main/kotlin/com/moa/entity/PaydayDay.kt
new file mode 100644
index 0000000..e3798a5
--- /dev/null
+++ b/src/main/kotlin/com/moa/entity/PaydayDay.kt
@@ -0,0 +1,64 @@
+package com.moa.entity
+
+import jakarta.persistence.Column
+import jakarta.persistence.Embeddable
+import java.time.DayOfWeek
+import java.time.LocalDate
+import java.time.YearMonth
+
+/**
+ * 사용자가 설정한 급여일을 표현하는 Value Object 입니다.
+ *
+ * 급여일은 1일부터 31일 사이의 값만 허용하며,
+ * 실제 급여일 계산 시 월말 보정 및 주말 보정 규칙을 함께 제공합니다.
+ */
+@Embeddable
+data class PaydayDay(
+    @Column(name = "payday_day", nullable = false)
+    var value: Int = 25,
+) {
+    init {
+        require(value in 1..31) { "paydayDay must be between 1 and 31" }
+    }
+
+    /**
+     * 특정 연월에 적용되는 실제 급여일을 계산합니다.
+     *
+     * 설정한 급여일이 해당 월에 없으면 말일로 보정하고,
+     * 보정된 날짜가 주말이면 직전 금요일로 당깁니다.
+     *
+     * @param year 급여일을 계산할 연도
+     * @param month 급여일을 계산할 월
+     * @return 실제 적용되는 급여일
+     */
+    fun resolveEffectiveDate(year: Int, month: Int): LocalDate {
+        val yearMonth = YearMonth.of(year, month)
+        val baseDate = yearMonth.atDay(minOf(value, yearMonth.lengthOfMonth()))
+
+        return when (baseDate.dayOfWeek) {
+            DayOfWeek.SATURDAY -> baseDate.minusDays(1)
+            DayOfWeek.SUNDAY -> baseDate.minusDays(2)
+            else -> baseDate
+        }
+    }
+
+    /**
+     * 특정 날짜가 이 급여일 설정의 실제 급여일인지 판정합니다.
+     *
+     * @param date 판정할 날짜
+     * @return 해당 날짜가 실제 급여일이면 `true`
+     */
+    fun isPayday(date: LocalDate): Boolean =
+        resolveEffectiveDate(date.year, date.monthValue) == date
+
+    companion object {
+        /**
+         * 특정 날짜에 실제 급여일로 귀결되는 모든 급여일 설정 값을 반환합니다.
+         *
+         * @param date 기준 날짜
+         * @return 해당 날짜를 실제 급여일로 가지는 [PaydayDay] 집합
+         */
+        fun resolvingTo(date: LocalDate): Set<PaydayDay> =
+            (1..31).map(::PaydayDay).filterTo(mutableSetOf()) { it.isPayday(date) }
+    }
+}
diff --git a/src/main/kotlin/com/moa/entity/PayrollVersion.kt b/src/main/kotlin/com/moa/entity/PayrollVersion.kt
index 76eaf97..213001c 100644
--- a/src/main/kotlin/com/moa/entity/PayrollVersion.kt
+++ b/src/main/kotlin/com/moa/entity/PayrollVersion.kt
@@ -23,7 +23,3 @@ class PayrollVersion(
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     val id: Long = 0
 }
-
-enum class SalaryInputType {
-    ANNUAL, MONTHLY
-}
diff --git a/src/main/kotlin/com/moa/entity/Profile.kt b/src/main/kotlin/com/moa/entity/Profile.kt
index 086d14d..903319c 100644
--- a/src/main/kotlin/com/moa/entity/Profile.kt
+++ b/src/main/kotlin/com/moa/entity/Profile.kt
@@ -13,8 +13,8 @@ class Profile(
     @Column(nullable = true)
     var workplace: String? = null,
 
-    @Column(nullable = false)
-    var paydayDay: Int = 25,
+    @Embedded
+    var paydayDay: PaydayDay = PaydayDay(),
 ) : BaseEntity() {
 
     @Id
diff --git a/src/main/kotlin/com/moa/entity/SalaryInputType.kt b/src/main/kotlin/com/moa/entity/SalaryInputType.kt
new file mode 100644
index 0000000..2ba5a60
--- /dev/null
+++ b/src/main/kotlin/com/moa/entity/SalaryInputType.kt
@@ -0,0 +1,6 @@
+package com.moa.entity
+
+enum class SalaryInputType {
+    ANNUAL,
+    MONTHLY,
+}
diff --git a/src/main/kotlin/com/moa/entity/NotificationLog.kt b/src/main/kotlin/com/moa/entity/notification/NotificationLog.kt
similarity index 92%
rename from src/main/kotlin/com/moa/entity/NotificationLog.kt
rename to src/main/kotlin/com/moa/entity/notification/NotificationLog.kt
index 2ee6971..7f93ddf 100644
--- a/src/main/kotlin/com/moa/entity/NotificationLog.kt
+++ b/src/main/kotlin/com/moa/entity/notification/NotificationLog.kt
@@ -1,5 +1,6 @@
-package com.moa.entity
+package com.moa.entity.notification
 
+import com.moa.entity.BaseEntity
 import jakarta.persistence.*
 import java.time.LocalDate
 import java.time.LocalTime
diff --git a/src/main/kotlin/com/moa/entity/NotificationSetting.kt b/src/main/kotlin/com/moa/entity/notification/NotificationSetting.kt
similarity index 94%
rename from src/main/kotlin/com/moa/entity/NotificationSetting.kt
rename to src/main/kotlin/com/moa/entity/notification/NotificationSetting.kt
index cfe2f3e..eba777e 100644
--- a/src/main/kotlin/com/moa/entity/NotificationSetting.kt
+++ b/src/main/kotlin/com/moa/entity/notification/NotificationSetting.kt
@@ -1,5 +1,6 @@
-package com.moa.entity
+package com.moa.entity.notification
 
+import com.moa.entity.BaseEntity
 import jakarta.persistence.*
 
 @Entity
diff --git a/src/main/kotlin/com/moa/entity/NotificationSettingType.kt b/src/main/kotlin/com/moa/entity/notification/NotificationSettingType.kt
similarity index 88%
rename from src/main/kotlin/com/moa/entity/NotificationSettingType.kt
rename to src/main/kotlin/com/moa/entity/notification/NotificationSettingType.kt
index de718bc..43a834a 100644
--- a/src/main/kotlin/com/moa/entity/NotificationSettingType.kt
+++ b/src/main/kotlin/com/moa/entity/notification/NotificationSettingType.kt
@@ -1,4 +1,4 @@
-package com.moa.entity
+package com.moa.entity.notification
 
 enum class NotificationSettingType(
     val category: String,
diff --git a/src/main/kotlin/com/moa/entity/NotificationStatus.kt b/src/main/kotlin/com/moa/entity/notification/NotificationStatus.kt
similarity index 70%
rename from src/main/kotlin/com/moa/entity/NotificationStatus.kt
rename to src/main/kotlin/com/moa/entity/notification/NotificationStatus.kt
index c527921..25cc1ae 100644
--- a/src/main/kotlin/com/moa/entity/NotificationStatus.kt
+++ b/src/main/kotlin/com/moa/entity/notification/NotificationStatus.kt
@@ -1,4 +1,4 @@
-package com.moa.entity
+package com.moa.entity.notification
 
 enum class NotificationStatus {
     PENDING,
diff --git a/src/main/kotlin/com/moa/entity/NotificationType.kt b/src/main/kotlin/com/moa/entity/notification/NotificationType.kt
similarity index 91%
rename from src/main/kotlin/com/moa/entity/NotificationType.kt
rename to src/main/kotlin/com/moa/entity/notification/NotificationType.kt
index 920ec70..8c1a529 100644
--- a/src/main/kotlin/com/moa/entity/NotificationType.kt
+++ b/src/main/kotlin/com/moa/entity/notification/NotificationType.kt
@@ -1,4 +1,4 @@
-package com.moa.entity
+package com.moa.entity.notification
 
 enum class NotificationType(
     val title: String,
diff --git a/src/main/kotlin/com/moa/repository/NotificationLogRepository.kt b/src/main/kotlin/com/moa/repository/NotificationLogRepository.kt
index e8d415c..cf36564 100644
--- a/src/main/kotlin/com/moa/repository/NotificationLogRepository.kt
+++ b/src/main/kotlin/com/moa/repository/NotificationLogRepository.kt
@@ -1,8 +1,8 @@
 package com.moa.repository
 
-import com.moa.entity.NotificationLog
-import com.moa.entity.NotificationStatus
-import com.moa.entity.NotificationType
+import com.moa.entity.notification.NotificationLog
+import com.moa.entity.notification.NotificationStatus
+import com.moa.entity.notification.NotificationType
 import org.springframework.data.jpa.repository.JpaRepository
 import java.time.LocalDate
 import java.time.LocalTime
diff --git a/src/main/kotlin/com/moa/repository/NotificationSettingRepository.kt b/src/main/kotlin/com/moa/repository/NotificationSettingRepository.kt
index 893fa99..a111d08 100644
--- a/src/main/kotlin/com/moa/repository/NotificationSettingRepository.kt
+++ b/src/main/kotlin/com/moa/repository/NotificationSettingRepository.kt
@@ -1,6 +1,6 @@
 package com.moa.repository
 
-import com.moa.entity.NotificationSetting
+import com.moa.entity.notification.NotificationSetting
 import org.springframework.data.jpa.repository.JpaRepository
 
 interface NotificationSettingRepository : JpaRepository<NotificationSetting, Long> {
diff --git a/src/main/kotlin/com/moa/repository/ProfileRepository.kt b/src/main/kotlin/com/moa/repository/ProfileRepository.kt
index 6764dc8..13c873e 100644
--- a/src/main/kotlin/com/moa/repository/ProfileRepository.kt
+++ b/src/main/kotlin/com/moa/repository/ProfileRepository.kt
@@ -5,5 +5,5 @@ import org.springframework.data.jpa.repository.JpaRepository
 
 interface ProfileRepository : JpaRepository<Profile, Long> {
     fun findByMemberId(memberId: Long): Profile?
-    fun findAllByPaydayDayIn(paydayDays: Collection<Int>): List<Profile>
+    fun findAllByPaydayDay_ValueIn(paydayDayValues: Collection<Int>): List<Profile>
 }
diff --git a/src/main/kotlin/com/moa/service/OnboardingStatusService.kt b/src/main/kotlin/com/moa/service/OnboardingStatusService.kt
index 15b3207..60e4480 100644
--- a/src/main/kotlin/com/moa/service/OnboardingStatusService.kt
+++ b/src/main/kotlin/com/moa/service/OnboardingStatusService.kt
@@ -27,7 +27,7 @@ class OnboardingStatusService(
                 ProfileResponse(
                     nickname = it.nickname,
                     workplace = it.workplace,
-                    paydayDay = it.paydayDay,
+                    paydayDay = it.paydayDay.value,
                 )
             }
 
diff --git a/src/main/kotlin/com/moa/service/PaydayResolver.kt b/src/main/kotlin/com/moa/service/PaydayResolver.kt
deleted file mode 100644
index 51bfb38..0000000
--- a/src/main/kotlin/com/moa/service/PaydayResolver.kt
+++ /dev/null
@@ -1,17 +0,0 @@
-package com.moa.service
-
-import java.time.DayOfWeek
-import java.time.LocalDate
-import java.time.YearMonth
-
-// 월급일이 해당 월에 없으면 말일로 보정하고, 그 날짜가 주말이면 직전 금요일로 당긴다.
-fun resolveEffectivePayday(year: Int, month: Int, paydayDay: Int): LocalDate {
-    val yearMonth = YearMonth.of(year, month)
-    val baseDate = yearMonth.atDay(minOf(paydayDay, yearMonth.lengthOfMonth()))
-
-    return when (baseDate.dayOfWeek) {
-        DayOfWeek.SATURDAY -> baseDate.minusDays(1)
-        DayOfWeek.SUNDAY -> baseDate.minusDays(2)
-        else -> baseDate
-    }
-}
diff --git a/src/main/kotlin/com/moa/service/ProfileService.kt b/src/main/kotlin/com/moa/service/ProfileService.kt
index 31a7bae..00b3e22 100644
--- a/src/main/kotlin/com/moa/service/ProfileService.kt
+++ b/src/main/kotlin/com/moa/service/ProfileService.kt
@@ -3,6 +3,7 @@ package com.moa.service
 import com.moa.common.exception.BadRequestException
 import com.moa.common.exception.ErrorCode
 import com.moa.common.exception.NotFoundException
+import com.moa.entity.PaydayDay
 import com.moa.entity.Profile
 import com.moa.repository.ProfileRepository
 import com.moa.service.dto.NicknameUpdateRequest
@@ -25,7 +26,7 @@ class ProfileService(
         return ProfileResponse(
             nickname = profile.nickname,
             workplace = profile.workplace,
-            paydayDay = profile.paydayDay,
+            paydayDay = profile.paydayDay.value,
         )
     }
 
@@ -45,7 +46,7 @@ class ProfileService(
         return ProfileResponse(
             nickname = profile.nickname,
             workplace = profile.workplace,
-            paydayDay = profile.paydayDay,
+            paydayDay = profile.paydayDay.value,
         )
     }
 
@@ -59,7 +60,7 @@ class ProfileService(
         return ProfileResponse(
             nickname = profile.nickname,
             workplace = profile.workplace,
-            paydayDay = profile.paydayDay,
+            paydayDay = profile.paydayDay.value,
         )
     }
 
@@ -73,25 +74,25 @@ class ProfileService(
         return ProfileResponse(
             nickname = profile.nickname,
             workplace = profile.workplace,
-            paydayDay = profile.paydayDay,
+            paydayDay = profile.paydayDay.value,
         )
     }
 
     @Transactional
     fun updatePayday(memberId: Long, req: PaydayUpdateRequest): ProfileResponse {
-        if (req.paydayDay !in 1..31) {
-            throw BadRequestException(ErrorCode.INVALID_PAYDAY_INPUT)
-        }
-
         val profile = profileRepository.findByMemberId(memberId)
             ?: throw NotFoundException()
 
-        profile.paydayDay = req.paydayDay
+        profile.paydayDay = try {
+            PaydayDay(req.paydayDay)
+        } catch (_: IllegalArgumentException) {
+            throw BadRequestException(ErrorCode.INVALID_PAYDAY_INPUT)
+        }
 
         return ProfileResponse(
             nickname = profile.nickname,
             workplace = profile.workplace,
-            paydayDay = profile.paydayDay,
+            paydayDay = profile.paydayDay.value,
         )
     }
 }
diff --git a/src/main/kotlin/com/moa/service/WorkdayService.kt b/src/main/kotlin/com/moa/service/WorkdayService.kt
index 382383f..bd11f69 100644
--- a/src/main/kotlin/com/moa/service/WorkdayService.kt
+++ b/src/main/kotlin/com/moa/service/WorkdayService.kt
@@ -7,13 +7,14 @@ import com.moa.entity.*
 import com.moa.repository.DailyWorkScheduleRepository
 import com.moa.repository.ProfileRepository
 import com.moa.repository.WorkPolicyVersionRepository
+import com.moa.service.calculator.EarningsCalculator
+import com.moa.service.calculator.SalaryCalculator
 import com.moa.service.dto.*
 import com.moa.service.notification.NotificationSyncService
 import org.springframework.stereotype.Service
 import org.springframework.transaction.annotation.Transactional
 import java.math.BigDecimal
 import java.time.LocalDate
-import java.time.LocalDateTime
 import java.time.LocalTime
 
 @Service
@@ -23,6 +24,7 @@ class WorkdayService(
     private val profileRepository: ProfileRepository,
     private val notificationSyncService: NotificationSyncService,
     private val earningsCalculator: EarningsCalculator,
+    private val salaryCalculator: SalaryCalculator,
 ) {
 
     @Transactional(readOnly = true)
@@ -69,12 +71,12 @@ class WorkdayService(
             )
         }
 
-        val policyDailyMinutes = SalaryCalculator.calculateWorkMinutes(
+        val policyDailyMinutes = salaryCalculator.calculateWorkMinutes(
             monthlyPolicy.clockInTime, monthlyPolicy.clockOutTime,
         )
 
         val policyWorkDayOfWeeks = monthlyPolicy.workdays.map { it.dayOfWeek }.toSet()
-        val workDaysInMonth = SalaryCalculator.getWorkDaysInPeriod(
+        val workDaysInMonth = salaryCalculator.getWorkDaysInPeriod(
             start = start,
             end = end.plusDays(1),
             workDays = policyWorkDayOfWeeks
@@ -99,16 +101,18 @@ class WorkdayService(
         var date = start
         while (!date.isAfter(lastCalculableDate)) {
             val schedule = resolveScheduleForDate(savedSchedulesByDate[date], monthlyPolicy, date)
-            val status = resolveDailyWorkStatus(date, schedule)
+            val status = DailyWorkStatusType.resolve(
+                date = date,
+                scheduleType = schedule.type,
+                clockIn = schedule.clockIn,
+                clockOut = schedule.clockOut,
+            )
             val adjustedClockOut = resolveClockOutForEarnings(date, today, now, schedule)
             val isCompletedWork = status == DailyWorkStatusType.COMPLETED &&
                     (schedule.type == DailyWorkScheduleType.WORK || schedule.type == DailyWorkScheduleType.VACATION)
 
             if (isCompletedWork && schedule.clockIn != null && adjustedClockOut != null) {
-                workedMinutes += SalaryCalculator.calculateWorkMinutes(schedule.clockIn, adjustedClockOut)
-            }
-
-            if (isCompletedWork) {
+                workedMinutes += salaryCalculator.calculateWorkMinutes(schedule.clockIn, adjustedClockOut)
                 val dailyEarnings = earningsCalculator.calculateDailyEarnings(
                     memberId, date, monthlyPolicy, schedule.type, schedule.clockIn, adjustedClockOut,
                 )
@@ -292,9 +296,9 @@ class WorkdayService(
         date: LocalDate,
         schedule: ResolvedSchedule,
         policy: WorkPolicyVersion?,
-        paydayDay: Int,
+        paydayDay: PaydayDay,
     ): WorkdayResponse {
-        val events = resolveDailyEvents(date, paydayDay)
+        val events = DailyEventType.resolve(date, paydayDay)
 
         if (schedule.type == DailyWorkScheduleType.NONE) {
             return WorkdayResponse(
@@ -308,7 +312,12 @@ class WorkdayService(
         val resolvedPolicy = policy ?: return WorkdayResponse(
             date = date,
             type = schedule.type,
-            status = resolveDailyWorkStatus(date, schedule),
+            status = DailyWorkStatusType.resolve(
+                date = date,
+                scheduleType = schedule.type,
+                clockIn = schedule.clockIn,
+                clockOut = schedule.clockOut,
+            ),
             events = events,
             dailyPay = 0,
             clockInTime = schedule.clockIn,
@@ -320,7 +329,12 @@ class WorkdayService(
         return WorkdayResponse(
             date = date,
             type = schedule.type,
-            status = resolveDailyWorkStatus(date, schedule),
+            status = DailyWorkStatusType.resolve(
+                date = date,
+                scheduleType = schedule.type,
+                clockIn = schedule.clockIn,
+                clockOut = schedule.clockOut,
+            ),
             events = events,
             dailyPay = earnings?.toInt() ?: 0,
             clockInTime = schedule.clockIn,
@@ -344,43 +358,9 @@ class WorkdayService(
             )
     }
 
-    private fun resolvePaydayDay(memberId: Long): Int =
+    private fun resolvePaydayDay(memberId: Long): PaydayDay =
         profileRepository.findByMemberId(memberId)?.paydayDay ?: throw NotFoundException()
 
-    private fun resolveDailyEvents(date: LocalDate, paydayDay: Int): List<DailyEventType> {
-        val events = mutableListOf<DailyEventType>()
-
-        if (isPayday(date, paydayDay)) {
-            events += DailyEventType.PAYDAY
-        }
-
-        // TODO: Add holiday event resolution when holiday data is available.
-
-        return events
-    }
-
-    private fun isPayday(date: LocalDate, paydayDay: Int): Boolean {
-        return resolveEffectivePayday(date.year, date.monthValue, paydayDay) == date
-    }
-
-    private fun resolveDailyWorkStatus(
-        date: LocalDate,
-        schedule: ResolvedSchedule,
-    ): DailyWorkStatusType {
-        if (schedule.type == DailyWorkScheduleType.NONE) return DailyWorkStatusType.NONE
-
-        val clockIn = schedule.clockIn ?: return DailyWorkStatusType.NONE
-        val clockOut = schedule.clockOut ?: return DailyWorkStatusType.NONE
-        val now = LocalDateTime.now()
-        val endAt = if (!clockOut.isBefore(clockIn)) {
-            date.atTime(clockOut)
-        } else {
-            date.plusDays(1).atTime(clockOut)
-        }
-
-        return if (now.isBefore(endAt)) DailyWorkStatusType.SCHEDULED else DailyWorkStatusType.COMPLETED
-    }
-
     private fun resolveClockOutForEarnings(
         targetDate: LocalDate,
         today: LocalDate,
diff --git a/src/main/kotlin/com/moa/service/EarningsCalculator.kt b/src/main/kotlin/com/moa/service/calculator/EarningsCalculator.kt
similarity index 79%
rename from src/main/kotlin/com/moa/service/EarningsCalculator.kt
rename to src/main/kotlin/com/moa/service/calculator/EarningsCalculator.kt
index 8cc3b10..37c6ac0 100644
--- a/src/main/kotlin/com/moa/service/EarningsCalculator.kt
+++ b/src/main/kotlin/com/moa/service/calculator/EarningsCalculator.kt
@@ -1,8 +1,7 @@
-package com.moa.service
+package com.moa.service.calculator
 
 import com.moa.entity.DailyWorkScheduleType
-import com.moa.entity.SalaryCalculator
-import com.moa.entity.SalaryType
+import com.moa.entity.SalaryInputType
 import com.moa.entity.WorkPolicyVersion
 import com.moa.repository.PayrollVersionRepository
 import org.springframework.stereotype.Service
@@ -19,13 +18,14 @@ import java.time.YearMonth
 @Service
 class EarningsCalculator(
     private val payrollVersionRepository: PayrollVersionRepository,
+    private val salaryCalculator: SalaryCalculator,
 ) {
     /**
      * 지정된 날짜가 속한 월을 기준으로 직원의 기본 월급을 계산합니다.
      *
      * 주어진 날짜가 속한 달의 마지막 날을 기준으로, 해당 시점에 유효한 가장 최근의 급여 정보를 바탕으로 계산합니다.
-     * 급여 유형이 연봉([SalaryType.YEARLY])인 경우 12로 나눈 후 소수점 첫째 자리에서 반올림(HALF_UP)한 값을 반환하며,
-     * 월급([SalaryType.MONTHLY])인 경우 계약된 금액을 그대로 반환합니다.
+     * 급여 유형이 연봉([com.moa.entity.SalaryInputType.ANNUAL])인 경우 12로 나눈 후 소수점 첫째 자리에서 반올림(HALF_UP)한 값을 반환하며,
+     * 월급([com.moa.entity.SalaryInputType.MONTHLY])인 경우 계약된 금액을 그대로 반환합니다.
      *
      * @param memberId 직원의 고유 식별자
      * @param date 기준 날짜 (이 날짜가 속한 월의 마지막 날을 기준으로 유효한 급여 정책을 적용합니다)
@@ -38,11 +38,11 @@ class EarningsCalculator(
                 memberId, lastDayOfMonth,
             ) ?: return null
 
-        return when (SalaryType.from(payroll.salaryInputType)) {
-            SalaryType.YEARLY -> payroll.salaryAmount.toBigDecimal()
+        return when (payroll.salaryInputType) {
+            SalaryInputType.ANNUAL -> payroll.salaryAmount.toBigDecimal()
                 .divide(BigDecimal(12), 0, RoundingMode.HALF_UP).toLong()
 
-            SalaryType.MONTHLY -> payroll.salaryAmount
+            SalaryInputType.MONTHLY -> payroll.salaryAmount
         }
     }
 
@@ -51,7 +51,7 @@ class EarningsCalculator(
      *
      * 이 메서드는 직원의 근무 정책과 실제 출퇴근 시간을 비교하여 일일 소득을 산출합니다.
      * 다음과 같은 규칙이 적용됩니다:
-     * - 근무 일정이 없는 경우([DailyWorkScheduleType.NONE]) 소득은 `0`으로 계산됩니다.
+     * - 근무 일정이 없는 경우([com.moa.entity.DailyWorkScheduleType.NONE]) 소득은 `0`으로 계산됩니다.
      * - 실제 출근 시간([clockInTime])과 퇴근 시간([clockOutTime])이 모두 제공된 경우, 정책상의 소정 근로 시간과
      * 실제 근로 시간을 비율로 산정하여 급여를 일할 계산합니다.
      * - 출퇴근 시간 중 하나라도 누락된 경우, 해당 일자의 기본 일급(Daily Rate)을 그대로 반환합니다.
@@ -80,20 +80,20 @@ class EarningsCalculator(
                 memberId, lastDayOfMonth,
             ) ?: return null
 
-        val dailyRate = SalaryCalculator.calculateDailyRate(
+        val dailyRate = salaryCalculator.calculateDailyRate(
             targetDate = date,
-            salaryType = SalaryType.from(payroll.salaryInputType),
+            salaryType = payroll.salaryInputType,
             salaryAmount = payroll.salaryAmount,
             workDays = policy.workdays.map { it.dayOfWeek }.toSet(),
         )
         if (dailyRate == BigDecimal.ZERO) return dailyRate
 
         if (clockInTime != null && clockOutTime != null) {
-            val policyMinutes = SalaryCalculator.calculateWorkMinutes(
+            val policyMinutes = salaryCalculator.calculateWorkMinutes(
                 policy.clockInTime, policy.clockOutTime,
             )
-            val actualMinutes = SalaryCalculator.calculateWorkMinutes(clockInTime, clockOutTime)
-            return SalaryCalculator.calculateEarnings(dailyRate, policyMinutes, actualMinutes)
+            val actualMinutes = salaryCalculator.calculateWorkMinutes(clockInTime, clockOutTime)
+            return salaryCalculator.calculateEarnings(dailyRate, policyMinutes, actualMinutes)
         }
 
         return dailyRate
diff --git a/src/main/kotlin/com/moa/entity/SalaryType.kt b/src/main/kotlin/com/moa/service/calculator/SalaryCalculator.kt
similarity index 73%
rename from src/main/kotlin/com/moa/entity/SalaryType.kt
rename to src/main/kotlin/com/moa/service/calculator/SalaryCalculator.kt
index 8383572..988dff6 100644
--- a/src/main/kotlin/com/moa/entity/SalaryType.kt
+++ b/src/main/kotlin/com/moa/service/calculator/SalaryCalculator.kt
@@ -1,45 +1,24 @@
-package com.moa.entity
+package com.moa.service.calculator
 
+import com.moa.entity.SalaryInputType
+import org.springframework.stereotype.Service
 import java.math.BigDecimal
 import java.math.RoundingMode
 import java.time.*
 
 /**
- * 급여 산정 방식을 정의하는 열거형입니다.
+ * 급여, 일급, 근로 시간 등을 계산하는 서비스입니다.
+ * * 외부 상태를 가지지 않지만, 계산 책임을 애플리케이션 서비스로 통일하기 위해 Spring Bean으로 관리합니다.
  */
-enum class SalaryType {
-    /** 연봉 기반 산정 방식 */
-    YEARLY,
-
-    /** 월급 기반 산정 방식 */
-    MONTHLY;
-
-    companion object {
-        /**
-         * 입력된 급여 유형([SalaryInputType])을 내부 처리용 급여 산정 방식([SalaryType])으로 변환합니다.
-         *
-         * @param inputType 외부에서 입력된 급여 유형 (예: ANNUAL, MONTHLY)
-         * @return 매핑된 [SalaryType] 인스턴스
-         */
-        fun from(inputType: SalaryInputType): SalaryType = when (inputType) {
-            SalaryInputType.ANNUAL -> YEARLY
-            SalaryInputType.MONTHLY -> MONTHLY
-        }
-    }
-}
-
-/**
- * 급여, 일급, 근로 시간 등을 계산하는 순수 유틸리티 객체입니다.
- * * 외부 상태를 가지지 않으며, 제공된 파라미터만을 기반으로 계산을 수행합니다.
- */
-object SalaryCalculator {
+@Service
+class SalaryCalculator {
 
     /**
      * 특정 일자가 속한 달의 일일 급여(일급)를 계산합니다.
      *
      * 이 메서드는 직원의 월 기본급을 해당 월의 '총 소정 근로일수'로 나누어 일급을 산출합니다.
-     * 연봉([SalaryType.YEARLY])인 경우 금액을 12로 나누어 월 기본급을 먼저 구합니다.
-     * 최종 산출된 일급은 소수점 첫째 자리에서 반올림([RoundingMode.HALF_UP]) 처리됩니다.
+     * 연봉([com.moa.entity.SalaryInputType.ANNUAL])인 경우 금액을 12로 나누어 월 기본급을 먼저 구합니다.
+     * 최종 산출된 일급은 소수점 첫째 자리에서 반올림([java.math.RoundingMode.HALF_UP]) 처리됩니다.
      *
      * @param targetDate 기준 일자 (이 일자가 속한 월을 기준으로 총 근로일수를 계산합니다)
      * @param salaryType 급여 산정 방식 (연봉 또는 월급)
@@ -49,18 +28,18 @@ object SalaryCalculator {
      */
     fun calculateDailyRate(
         targetDate: LocalDate,
-        salaryType: SalaryType,
+        salaryType: SalaryInputType,
         salaryAmount: Long,
         workDays: Set<DayOfWeek>
     ): BigDecimal {
         val monthlySalary = when (salaryType) {
-            SalaryType.YEARLY -> salaryAmount.toBigDecimal().divide(BigDecimal(12), 0, RoundingMode.HALF_UP)
-            SalaryType.MONTHLY -> salaryAmount.toBigDecimal()
+            SalaryInputType.ANNUAL -> salaryAmount.toBigDecimal().divide(BigDecimal(12), 0, RoundingMode.HALF_UP)
+            SalaryInputType.MONTHLY -> salaryAmount.toBigDecimal()
         }
 
         val yearMonth = YearMonth.from(targetDate)
         val periodStart = yearMonth.atDay(1)
-        val periodEnd = yearMonth.atEndOfMonth().plusDays(1) // exclusive
+        val periodEnd = yearMonth.atEndOfMonth().plusDays(1)
 
         val workDaysCount = getWorkDaysInPeriod(periodStart, periodEnd, workDays)
 
diff --git a/src/main/kotlin/com/moa/service/dto/NotificationSettingResponse.kt b/src/main/kotlin/com/moa/service/dto/NotificationSettingResponse.kt
index 18856f2..341ad83 100644
--- a/src/main/kotlin/com/moa/service/dto/NotificationSettingResponse.kt
+++ b/src/main/kotlin/com/moa/service/dto/NotificationSettingResponse.kt
@@ -1,7 +1,7 @@
 package com.moa.service.dto
 
-import com.moa.entity.NotificationSetting
-import com.moa.entity.NotificationSettingType
+import com.moa.entity.notification.NotificationSetting
+import com.moa.entity.notification.NotificationSettingType
 
 data class NotificationSettingResponse(
     val type: NotificationSettingType,
diff --git a/src/main/kotlin/com/moa/service/dto/NotificationSettingUpdateRequest.kt b/src/main/kotlin/com/moa/service/dto/NotificationSettingUpdateRequest.kt
index 8335511..91b2052 100644
--- a/src/main/kotlin/com/moa/service/dto/NotificationSettingUpdateRequest.kt
+++ b/src/main/kotlin/com/moa/service/dto/NotificationSettingUpdateRequest.kt
@@ -1,6 +1,6 @@
 package com.moa.service.dto
 
-import com.moa.entity.NotificationSettingType
+import com.moa.entity.notification.NotificationSettingType
 
 data class NotificationSettingUpdateRequest(
     val type: NotificationSettingType,
diff --git a/src/main/kotlin/com/moa/service/notification/NotificationBatchService.kt b/src/main/kotlin/com/moa/service/notification/NotificationBatchService.kt
index 2c71c0f..289a63d 100644
--- a/src/main/kotlin/com/moa/service/notification/NotificationBatchService.kt
+++ b/src/main/kotlin/com/moa/service/notification/NotificationBatchService.kt
@@ -1,6 +1,9 @@
 package com.moa.service.notification
 
 import com.moa.entity.*
+import com.moa.entity.notification.NotificationLog
+import com.moa.entity.notification.NotificationSetting
+import com.moa.entity.notification.NotificationType
 import com.moa.repository.*
 import org.slf4j.LoggerFactory
 import org.springframework.stereotype.Service
diff --git a/src/main/kotlin/com/moa/service/notification/NotificationDispatchService.kt b/src/main/kotlin/com/moa/service/notification/NotificationDispatchService.kt
index e863b23..7762d19 100644
--- a/src/main/kotlin/com/moa/service/notification/NotificationDispatchService.kt
+++ b/src/main/kotlin/com/moa/service/notification/NotificationDispatchService.kt
@@ -1,7 +1,7 @@
 package com.moa.service.notification
 
-import com.moa.entity.NotificationLog
-import com.moa.entity.NotificationStatus
+import com.moa.entity.notification.NotificationLog
+import com.moa.entity.notification.NotificationStatus
 import com.moa.repository.FcmTokenRepository
 import com.moa.repository.NotificationLogRepository
 import com.moa.service.FcmService
diff --git a/src/main/kotlin/com/moa/service/notification/NotificationMessageBuilder.kt b/src/main/kotlin/com/moa/service/notification/NotificationMessageBuilder.kt
index b03261f..65ea138 100644
--- a/src/main/kotlin/com/moa/service/notification/NotificationMessageBuilder.kt
+++ b/src/main/kotlin/com/moa/service/notification/NotificationMessageBuilder.kt
@@ -1,11 +1,11 @@
 package com.moa.service.notification
 
 import com.moa.entity.DailyWorkScheduleType
-import com.moa.entity.NotificationLog
-import com.moa.entity.NotificationType
+import com.moa.entity.notification.NotificationLog
+import com.moa.entity.notification.NotificationType
 import com.moa.repository.DailyWorkScheduleRepository
 import com.moa.repository.WorkPolicyVersionRepository
-import com.moa.service.EarningsCalculator
+import com.moa.service.calculator.EarningsCalculator
 import org.springframework.stereotype.Service
 import java.math.BigDecimal
 import java.text.NumberFormat
diff --git a/src/main/kotlin/com/moa/service/notification/NotificationSettingService.kt b/src/main/kotlin/com/moa/service/notification/NotificationSettingService.kt
index 1f496e9..f27862f 100644
--- a/src/main/kotlin/com/moa/service/notification/NotificationSettingService.kt
+++ b/src/main/kotlin/com/moa/service/notification/NotificationSettingService.kt
@@ -1,9 +1,9 @@
 package com.moa.service.notification
 
-import com.moa.entity.NotificationSetting
-import com.moa.entity.NotificationSettingType
 import com.moa.entity.Term
 import com.moa.entity.TermAgreement
+import com.moa.entity.notification.NotificationSetting
+import com.moa.entity.notification.NotificationSettingType
 import com.moa.repository.NotificationSettingRepository
 import com.moa.repository.TermAgreementRepository
 import com.moa.service.dto.NotificationSettingResponse
diff --git a/src/main/kotlin/com/moa/service/notification/NotificationSyncService.kt b/src/main/kotlin/com/moa/service/notification/NotificationSyncService.kt
index 108331c..50694b2 100644
--- a/src/main/kotlin/com/moa/service/notification/NotificationSyncService.kt
+++ b/src/main/kotlin/com/moa/service/notification/NotificationSyncService.kt
@@ -1,9 +1,9 @@
 package com.moa.service.notification
 
 import com.moa.entity.DailyWorkScheduleType
-import com.moa.entity.NotificationLog
-import com.moa.entity.NotificationStatus
-import com.moa.entity.NotificationType
+import com.moa.entity.notification.NotificationLog
+import com.moa.entity.notification.NotificationStatus
+import com.moa.entity.notification.NotificationType
 import com.moa.repository.NotificationLogRepository
 import org.slf4j.LoggerFactory
 import org.springframework.stereotype.Service
diff --git a/src/main/kotlin/com/moa/service/notification/PaydayNotificationBatchService.kt b/src/main/kotlin/com/moa/service/notification/PaydayNotificationBatchService.kt
index 93a4072..c86b374 100644
--- a/src/main/kotlin/com/moa/service/notification/PaydayNotificationBatchService.kt
+++ b/src/main/kotlin/com/moa/service/notification/PaydayNotificationBatchService.kt
@@ -1,8 +1,12 @@
 package com.moa.service.notification
 
-import com.moa.entity.*
+import com.moa.entity.FcmToken
+import com.moa.entity.PaydayDay
+import com.moa.entity.Profile
+import com.moa.entity.notification.NotificationLog
+import com.moa.entity.notification.NotificationSetting
+import com.moa.entity.notification.NotificationType
 import com.moa.repository.*
-import com.moa.service.resolveEffectivePayday
 import org.slf4j.LoggerFactory
 import org.springframework.stereotype.Service
 import org.springframework.transaction.annotation.Transactional
@@ -49,14 +53,14 @@ class PaydayNotificationBatchService(
     }
 
     private fun findPaydayProfiles(date: LocalDate): List<Profile> {
-        val candidatePaydayDays = (1..31)
-            .filter { resolveEffectivePayday(date.year, date.monthValue, it) == date }
+        val candidatePaydayDays = PaydayDay.resolvingTo(date)
+            .map { it.value }
 
         if (candidatePaydayDays.isEmpty()) {
             return emptyList()
         }
 
-        return profileRepository.findAllByPaydayDayIn(candidatePaydayDays)
+        return profileRepository.findAllByPaydayDay_ValueIn(candidatePaydayDays)
     }
 
     private fun findRequiredTermCodes(): Set<String> =
diff --git a/src/main/resources/application-prod.yml b/src/main/resources/application-prod.yml
index 7022613..1dbfa01 100644
--- a/src/main/resources/application-prod.yml
+++ b/src/main/resources/application-prod.yml
@@ -8,7 +8,7 @@ spring:
   jpa:
     database-platform: org.hibernate.dialect.MySQLDialect
     hibernate:
-      ddl-auto: update
+      ddl-auto: validate
 
 jwt:
   secret-key: ${secret.jwt.prod.access.secret-key}
diff --git a/src/test/kotlin/com/moa/entity/DailyEventTypeTest.kt b/src/test/kotlin/com/moa/entity/DailyEventTypeTest.kt
new file mode 100644
index 0000000..4d8a208
--- /dev/null
+++ b/src/test/kotlin/com/moa/entity/DailyEventTypeTest.kt
@@ -0,0 +1,58 @@
+package com.moa.entity
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import java.time.LocalDate
+
+class DailyEventTypeTest {
+
+    @Test
+    fun `급여일과 같은 날짜면 PAYDAY 이벤트를 반환한다`() {
+        val result = DailyEventType.resolve(
+            date = LocalDate.of(2025, 6, 25),
+            paydayDay = PaydayDay(25),
+        )
+
+        assertThat(result).containsExactly(DailyEventType.PAYDAY)
+    }
+
+    @Test
+    fun `급여일과 다른 날짜면 빈 이벤트 목록을 반환한다`() {
+        val result = DailyEventType.resolve(
+            date = LocalDate.of(2025, 6, 24),
+            paydayDay = PaydayDay(25),
+        )
+
+        assertThat(result).isEmpty()
+    }
+
+    @Test
+    fun `설정한 급여일이 말일보다 크면 말일을 급여일로 간주한다`() {
+        val result = DailyEventType.resolve(
+            date = LocalDate.of(2025, 2, 28),
+            paydayDay = PaydayDay(31),
+        )
+
+        assertThat(result).containsExactly(DailyEventType.PAYDAY)
+    }
+
+    @Test
+    fun `말일 보정이 적용된 달에서도 말일 이전 날짜는 급여일이 아니다`() {
+        val result = DailyEventType.resolve(
+            date = LocalDate.of(2025, 2, 27),
+            paydayDay = PaydayDay(31),
+        )
+
+        assertThat(result).isEmpty()
+    }
+
+    @Test
+    fun `설정한 급여일이 주말이면 직전 평일을 급여일로 간주한다`() {
+        val result = DailyEventType.resolve(
+            date = LocalDate.of(2025, 5, 30),
+            paydayDay = PaydayDay(31),
+        )
+
+        assertThat(result).containsExactly(DailyEventType.PAYDAY)
+    }
+}
diff --git a/src/test/kotlin/com/moa/entity/DailyWorkStatusTypeTest.kt b/src/test/kotlin/com/moa/entity/DailyWorkStatusTypeTest.kt
new file mode 100644
index 0000000..18537b2
--- /dev/null
+++ b/src/test/kotlin/com/moa/entity/DailyWorkStatusTypeTest.kt
@@ -0,0 +1,64 @@
+package com.moa.entity
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import java.time.LocalDate
+import java.time.LocalDateTime
+import java.time.LocalTime
+
+class DailyWorkStatusTypeTest {
+
+    private val date = LocalDate.of(2025, 6, 9)
+
+    @Test
+    fun `근무 유형이 NONE이면 NONE을 반환한다`() {
+        val result = DailyWorkStatusType.resolve(
+            date = date,
+            scheduleType = DailyWorkScheduleType.NONE,
+            clockIn = LocalTime.of(9, 0),
+            clockOut = LocalTime.of(18, 0),
+            now = date.atTime(12, 0),
+        )
+
+        assertThat(result).isEqualTo(DailyWorkStatusType.NONE)
+    }
+
+    @Test
+    fun `종료 시각 전이면 SCHEDULED를 반환한다`() {
+        val result = DailyWorkStatusType.resolve(
+            date = date,
+            scheduleType = DailyWorkScheduleType.WORK,
+            clockIn = LocalTime.of(9, 0),
+            clockOut = LocalTime.of(18, 0),
+            now = date.atTime(17, 59),
+        )
+
+        assertThat(result).isEqualTo(DailyWorkStatusType.SCHEDULED)
+    }
+
+    @Test
+    fun `종료 시각 이후면 COMPLETED를 반환한다`() {
+        val result = DailyWorkStatusType.resolve(
+            date = date,
+            scheduleType = DailyWorkScheduleType.WORK,
+            clockIn = LocalTime.of(9, 0),
+            clockOut = LocalTime.of(18, 0),
+            now = date.atTime(18, 0),
+        )
+
+        assertThat(result).isEqualTo(DailyWorkStatusType.COMPLETED)
+    }
+
+    @Test
+    fun `자정 넘김 근무는 익일 종료 시각 기준으로 판정한다`() {
+        val result = DailyWorkStatusType.resolve(
+            date = date,
+            scheduleType = DailyWorkScheduleType.WORK,
+            clockIn = LocalTime.of(22, 0),
+            clockOut = LocalTime.of(2, 0),
+            now = LocalDateTime.of(2025, 6, 10, 1, 0),
+        )
+
+        assertThat(result).isEqualTo(DailyWorkStatusType.SCHEDULED)
+    }
+}
diff --git a/src/test/kotlin/com/moa/entity/PaydayDayTest.kt b/src/test/kotlin/com/moa/entity/PaydayDayTest.kt
new file mode 100644
index 0000000..067d311
--- /dev/null
+++ b/src/test/kotlin/com/moa/entity/PaydayDayTest.kt
@@ -0,0 +1,40 @@
+package com.moa.entity
+
+import org.assertj.core.api.Assertions.assertThat
+import org.assertj.core.api.Assertions.assertThatThrownBy
+import org.junit.jupiter.api.Test
+import java.time.LocalDate
+
+class PaydayDayTest {
+
+    @Test
+    fun `급여일은 1일부터 31일까지의 값만 허용한다`() {
+        assertThatThrownBy { PaydayDay(0) }
+            .isInstanceOf(IllegalArgumentException::class.java)
+
+        assertThatThrownBy { PaydayDay(32) }
+            .isInstanceOf(IllegalArgumentException::class.java)
+    }
+
+    @Test
+    fun `설정한 급여일이 해당 월에 없으면 말일로 보정한다`() {
+        val result = PaydayDay(31).resolveEffectiveDate(2025, 2)
+
+        assertThat(result).isEqualTo(LocalDate.of(2025, 2, 28))
+    }
+
+    @Test
+    fun `실제 급여일이 주말이면 직전 금요일로 당긴다`() {
+        val result = PaydayDay(31).resolveEffectiveDate(2025, 5)
+
+        assertThat(result).isEqualTo(LocalDate.of(2025, 5, 30))
+    }
+
+    @Test
+    fun `특정 날짜가 실제 급여일인지 판정할 수 있다`() {
+        val paydayDay = PaydayDay(25)
+
+        assertThat(paydayDay.isPayday(LocalDate.of(2025, 6, 25))).isTrue()
+        assertThat(paydayDay.isPayday(LocalDate.of(2025, 6, 24))).isFalse()
+    }
+}
diff --git a/src/test/kotlin/com/moa/service/fcm/FcmSendLearningTest.kt b/src/test/kotlin/com/moa/learning/fcm/FcmSendLearningTest.kt
similarity index 98%
rename from src/test/kotlin/com/moa/service/fcm/FcmSendLearningTest.kt
rename to src/test/kotlin/com/moa/learning/fcm/FcmSendLearningTest.kt
index 99f5e79..97d79d8 100644
--- a/src/test/kotlin/com/moa/service/fcm/FcmSendLearningTest.kt
+++ b/src/test/kotlin/com/moa/learning/fcm/FcmSendLearningTest.kt
@@ -1,4 +1,4 @@
-package com.moa.service.fcm
+package com.moa.learning.fcm
 
 import com.google.auth.oauth2.GoogleCredentials
 import com.google.firebase.FirebaseApp
diff --git a/src/test/kotlin/com/moa/repository/ProfileRepositoryTest.kt b/src/test/kotlin/com/moa/repository/ProfileRepositoryTest.kt
new file mode 100644
index 0000000..0368dba
--- /dev/null
+++ b/src/test/kotlin/com/moa/repository/ProfileRepositoryTest.kt
@@ -0,0 +1,65 @@
+package com.moa.repository
+
+import com.moa.entity.PaydayDay
+import com.moa.entity.Profile
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.boot.data.jpa.test.autoconfigure.DataJpaTest
+
+@DataJpaTest
+class ProfileRepositoryTest @Autowired constructor(
+    private val profileRepository: ProfileRepository,
+) {
+
+    @Test
+    fun `paydayDay value 목록에 포함되는 프로필만 조회한다`() {
+        val included = profileRepository.save(
+            Profile(
+                memberId = 1L,
+                nickname = "included",
+                paydayDay = PaydayDay(25),
+            ),
+        )
+        profileRepository.save(
+            Profile(
+                memberId = 2L,
+                nickname = "excluded",
+                paydayDay = PaydayDay(10),
+            ),
+        )
+
+        val result = profileRepository.findAllByPaydayDay_ValueIn(listOf(25, 31))
+
+        assertThat(result.map { it.id }).containsExactly(included.id)
+    }
+
+    @Test
+    fun `여러 paydayDay value를 전달하면 해당 값들을 가진 프로필을 모두 조회한다`() {
+        val first = profileRepository.save(
+            Profile(
+                memberId = 3L,
+                nickname = "first",
+                paydayDay = PaydayDay(25),
+            ),
+        )
+        val second = profileRepository.save(
+            Profile(
+                memberId = 4L,
+                nickname = "second",
+                paydayDay = PaydayDay(31),
+            ),
+        )
+        profileRepository.save(
+            Profile(
+                memberId = 5L,
+                nickname = "third",
+                paydayDay = PaydayDay(12),
+            ),
+        )
+
+        val result = profileRepository.findAllByPaydayDay_ValueIn(listOf(25, 31))
+
+        assertThat(result.map { it.id }).containsExactlyInAnyOrder(first.id, second.id)
+    }
+}
diff --git a/src/test/kotlin/com/moa/service/EarningsCalculatorTest.kt b/src/test/kotlin/com/moa/service/calculator/EarningsCalculatorTest.kt
similarity index 98%
rename from src/test/kotlin/com/moa/service/EarningsCalculatorTest.kt
rename to src/test/kotlin/com/moa/service/calculator/EarningsCalculatorTest.kt
index beb021a..1fa68d6 100644
--- a/src/test/kotlin/com/moa/service/EarningsCalculatorTest.kt
+++ b/src/test/kotlin/com/moa/service/calculator/EarningsCalculatorTest.kt
@@ -1,4 +1,4 @@
-package com.moa.service
+package com.moa.service.calculator
 
 import com.moa.entity.*
 import com.moa.repository.PayrollVersionRepository
@@ -16,7 +16,8 @@ import java.time.LocalTime
 class EarningsCalculatorTest {
 
     private val payrollVersionRepository: PayrollVersionRepository = mockk()
-    private val sut = EarningsCalculator(payrollVersionRepository)
+    private val salaryCalculator = SalaryCalculator()
+    private val sut = EarningsCalculator(payrollVersionRepository, salaryCalculator)
 
     companion object {
         private const val MEMBER_ID = 1L
diff --git a/src/test/kotlin/com/moa/entity/SalaryCalculatorTest.kt b/src/test/kotlin/com/moa/service/calculator/SalaryCalculatorTest.kt
similarity index 68%
rename from src/test/kotlin/com/moa/entity/SalaryCalculatorTest.kt
rename to src/test/kotlin/com/moa/service/calculator/SalaryCalculatorTest.kt
index 6dbc380..bd2c687 100644
--- a/src/test/kotlin/com/moa/entity/SalaryCalculatorTest.kt
+++ b/src/test/kotlin/com/moa/service/calculator/SalaryCalculatorTest.kt
@@ -1,6 +1,7 @@
-package com.moa.entity
+package com.moa.service.calculator
 
-import org.assertj.core.api.Assertions.assertThat
+import com.moa.entity.SalaryInputType
+import org.assertj.core.api.Assertions
 import org.junit.jupiter.api.Test
 import java.math.BigDecimal
 import java.math.RoundingMode
@@ -9,6 +10,7 @@ import java.time.LocalDate
 import java.time.LocalTime
 
 class SalaryCalculatorTest {
+    private val salaryCalculator = SalaryCalculator()
 
     companion object {
         private val WEEKDAYS = setOf(
@@ -25,15 +27,15 @@ class SalaryCalculatorTest {
         val targetDate = LocalDate.of(2025, 2, 3)
         val monthlySalary = 3_000_000L
 
-        val result = SalaryCalculator.calculateDailyRate(
+        val result = salaryCalculator.calculateDailyRate(
             targetDate = targetDate,
-            salaryType = SalaryType.MONTHLY,
+            salaryType = SalaryInputType.MONTHLY,
             salaryAmount = monthlySalary,
             workDays = WEEKDAYS,
         )
 
         val expected = BigDecimal(3_000_000).divide(BigDecimal(20), 0, RoundingMode.HALF_UP)
-        assertThat(result).isEqualByComparingTo(expected)
+        Assertions.assertThat(result).isEqualByComparingTo(expected)
     }
 
     // --- 연봉 기반 일급 계산 ---
@@ -44,16 +46,16 @@ class SalaryCalculatorTest {
         val targetDate = LocalDate.of(2025, 2, 3)
         val yearlySalary = 36_000_000L
 
-        val result = SalaryCalculator.calculateDailyRate(
+        val result = salaryCalculator.calculateDailyRate(
             targetDate = targetDate,
-            salaryType = SalaryType.YEARLY,
+            salaryType = SalaryInputType.ANNUAL,
             salaryAmount = yearlySalary,
             workDays = WEEKDAYS,
         )
 
         val expected = BigDecimal(36_000_000).divide(BigDecimal(12), 0, RoundingMode.HALF_UP)
             .divide(BigDecimal(20), 0, RoundingMode.HALF_UP)
-        assertThat(result).isEqualByComparingTo(expected)
+        Assertions.assertThat(result).isEqualByComparingTo(expected)
     }
 
     // --- 월별 근무일수 차이 ---
@@ -63,15 +65,15 @@ class SalaryCalculatorTest {
         // 2025년 3월: 평일 21일
         val targetDate = LocalDate.of(2025, 3, 10)
 
-        val result = SalaryCalculator.calculateDailyRate(
+        val result = salaryCalculator.calculateDailyRate(
             targetDate = targetDate,
-            salaryType = SalaryType.MONTHLY,
+            salaryType = SalaryInputType.MONTHLY,
             salaryAmount = 2_100_000L,
             workDays = WEEKDAYS,
         )
 
         val expected = BigDecimal(2_100_000).divide(BigDecimal(21), 0, RoundingMode.HALF_UP)
-        assertThat(result).isEqualByComparingTo(expected)
+        Assertions.assertThat(result).isEqualByComparingTo(expected)
     }
 
     @Test
@@ -79,15 +81,15 @@ class SalaryCalculatorTest {
         // 2025년 1월: 평일 23일
         val targetDate = LocalDate.of(2025, 1, 15)
 
-        val result = SalaryCalculator.calculateDailyRate(
+        val result = salaryCalculator.calculateDailyRate(
             targetDate = targetDate,
-            salaryType = SalaryType.MONTHLY,
+            salaryType = SalaryInputType.MONTHLY,
             salaryAmount = 2_300_000L,
             workDays = WEEKDAYS,
         )
 
         val expected = BigDecimal(2_300_000).divide(BigDecimal(23), 0, RoundingMode.HALF_UP)
-        assertThat(result).isEqualByComparingTo(expected)
+        Assertions.assertThat(result).isEqualByComparingTo(expected)
     }
 
     // --- 2월 처리 ---
@@ -97,15 +99,15 @@ class SalaryCalculatorTest {
         // 2025년 2월 (비윤년): 평일 20일
         val targetDate = LocalDate.of(2025, 2, 10)
 
-        val result = SalaryCalculator.calculateDailyRate(
+        val result = salaryCalculator.calculateDailyRate(
             targetDate = targetDate,
-            salaryType = SalaryType.MONTHLY,
+            salaryType = SalaryInputType.MONTHLY,
             salaryAmount = 2_000_000L,
             workDays = WEEKDAYS,
         )
 
         val expected = BigDecimal(2_000_000).divide(BigDecimal(20), 0, RoundingMode.HALF_UP)
-        assertThat(result).isEqualByComparingTo(expected)
+        Assertions.assertThat(result).isEqualByComparingTo(expected)
     }
 
     @Test
@@ -113,15 +115,15 @@ class SalaryCalculatorTest {
         // 2024년 2월 (윤년): 평일 21일
         val targetDate = LocalDate.of(2024, 2, 10)
 
-        val result = SalaryCalculator.calculateDailyRate(
+        val result = salaryCalculator.calculateDailyRate(
             targetDate = targetDate,
-            salaryType = SalaryType.MONTHLY,
+            salaryType = SalaryInputType.MONTHLY,
             salaryAmount = 2_100_000L,
             workDays = WEEKDAYS,
         )
 
         val expected = BigDecimal(2_100_000).divide(BigDecimal(21), 0, RoundingMode.HALF_UP)
-        assertThat(result).isEqualByComparingTo(expected)
+        Assertions.assertThat(result).isEqualByComparingTo(expected)
     }
 
     // --- 근무요일 설정 ---
@@ -132,58 +134,58 @@ class SalaryCalculatorTest {
         // 2025년 2월: 월~토 = 24일
         val targetDate = LocalDate.of(2025, 2, 3)
 
-        val result = SalaryCalculator.calculateDailyRate(
+        val result = salaryCalculator.calculateDailyRate(
             targetDate = targetDate,
-            salaryType = SalaryType.MONTHLY,
+            salaryType = SalaryInputType.MONTHLY,
             salaryAmount = 2_400_000L,
             workDays = sixDayWork,
         )
 
         val expected = BigDecimal(2_400_000).divide(BigDecimal(24), 0, RoundingMode.HALF_UP)
-        assertThat(result).isEqualByComparingTo(expected)
+        Assertions.assertThat(result).isEqualByComparingTo(expected)
     }
 
     // --- 엣지 케이스 ---
 
     @Test
     fun `근무요일이 없으면 일급은 0을 반환한다`() {
-        val result = SalaryCalculator.calculateDailyRate(
+        val result = salaryCalculator.calculateDailyRate(
             targetDate = LocalDate.of(2025, 2, 3),
-            salaryType = SalaryType.MONTHLY,
+            salaryType = SalaryInputType.MONTHLY,
             salaryAmount = 3_000_000L,
             workDays = emptySet(),
         )
 
-        assertThat(result).isEqualByComparingTo(BigDecimal.ZERO)
+        Assertions.assertThat(result).isEqualByComparingTo(BigDecimal.ZERO)
     }
 
     // --- 근무 시간(분) 계산 ---
 
     @Test
     fun `calculateWorkMinutes - 9시에서 18시는 540분을 반환한다`() {
-        val result = SalaryCalculator.calculateWorkMinutes(
+        val result = salaryCalculator.calculateWorkMinutes(
             LocalTime.of(9, 0),
             LocalTime.of(18, 0),
         )
-        assertThat(result).isEqualTo(540L)
+        Assertions.assertThat(result).isEqualTo(540L)
     }
 
     @Test
     fun `calculateWorkMinutes - 자정넘김 22시에서 2시는 240분을 반환한다`() {
-        val result = SalaryCalculator.calculateWorkMinutes(
+        val result = salaryCalculator.calculateWorkMinutes(
             LocalTime.of(22, 0),
             LocalTime.of(2, 0),
         )
-        assertThat(result).isEqualTo(240L)
+        Assertions.assertThat(result).isEqualTo(240L)
     }
 
     @Test
     fun `calculateWorkMinutes - 시작시간과 종료시간이 같으면 0분을 반환한다`() {
-        val result = SalaryCalculator.calculateWorkMinutes(
+        val result = salaryCalculator.calculateWorkMinutes(
             LocalTime.of(9, 0),
             LocalTime.of(9, 0),
         )
-        assertThat(result).isEqualTo(0L)
+        Assertions.assertThat(result).isEqualTo(0L)
     }
 
     // --- 실제 수입 계산 ---
@@ -191,45 +193,45 @@ class SalaryCalculatorTest {
     @Test
     fun `calculateEarnings - 실제 근무시간이 정책과 같으면 일급과 동일한 금액을 반환한다`() {
         val dailyRate = BigDecimal(150_000)
-        val result = SalaryCalculator.calculateEarnings(dailyRate, 540, 540)
-        assertThat(result).isEqualByComparingTo(dailyRate)
+        val result = salaryCalculator.calculateEarnings(dailyRate, 540, 540)
+        Assertions.assertThat(result).isEqualByComparingTo(dailyRate)
     }
 
     @Test
     fun `calculateEarnings - 초과 근무시 분급 기준으로 증가된 금액을 반환한다`() {
         val dailyRate = BigDecimal(150_000)
         // 540분 정책, 600분 실제 (1시간 초과)
-        val result = SalaryCalculator.calculateEarnings(dailyRate, 540, 600)
-        assertThat(result).isGreaterThan(dailyRate)
+        val result = salaryCalculator.calculateEarnings(dailyRate, 540, 600)
+        Assertions.assertThat(result).isGreaterThan(dailyRate)
     }
 
     @Test
     fun `calculateEarnings - 조기 퇴근시 분급 기준으로 감소된 금액을 반환한다`() {
         val dailyRate = BigDecimal(150_000)
         // 540분 정책, 480분 실제 (1시간 조기 퇴근)
-        val result = SalaryCalculator.calculateEarnings(dailyRate, 540, 480)
-        assertThat(result).isLessThan(dailyRate)
+        val result = salaryCalculator.calculateEarnings(dailyRate, 540, 480)
+        Assertions.assertThat(result).isLessThan(dailyRate)
     }
 
     @Test
     fun `같은 월급이라도 월마다 근무일수에 따라 일급이 달라진다`() {
         val salary = 3_000_000L
 
-        val febResult = SalaryCalculator.calculateDailyRate(
+        val febResult = salaryCalculator.calculateDailyRate(
             targetDate = LocalDate.of(2025, 2, 1),
-            salaryType = SalaryType.MONTHLY,
+            salaryType = SalaryInputType.MONTHLY,
             salaryAmount = salary,
             workDays = WEEKDAYS,
         )
 
-        val marResult = SalaryCalculator.calculateDailyRate(
+        val marResult = salaryCalculator.calculateDailyRate(
             targetDate = LocalDate.of(2025, 3, 1),
-            salaryType = SalaryType.MONTHLY,
+            salaryType = SalaryInputType.MONTHLY,
             salaryAmount = salary,
             workDays = WEEKDAYS,
         )
 
         // 2월(20일) > 3월(21일) → 2월 일급이 더 높아야 함
-        assertThat(febResult).isGreaterThan(marResult)
+        Assertions.assertThat(febResult).isGreaterThan(marResult)
     }
 }