diff --git a/src/features/shift/shiftApiSlice.ts b/src/features/shift/shiftApiSlice.ts
index 38eb19b..78b5804 100644
--- a/src/features/shift/shiftApiSlice.ts
+++ b/src/features/shift/shiftApiSlice.ts
@@ -27,12 +27,12 @@ export const shiftsApiSlice = apiSlice.injectEndpoints({
         const loaddedShifts = responseData.map((entity) => {
           // console.log('[loaddedShifts] entity: ', entity)
           entity.id = entity.id
-          if (!entity.timeWindowDisplay) {
-            entity.timeWindowDisplay =
-              formatMilitaryTime(entity.timeWindow.startTime) +
-              ' - ' +
-              formatMilitaryTime(entity.timeWindow.endTime)
-          }
+          // if (!entity.timeWindowDisplay) {
+          //   entity.timeWindowDisplay =
+          //     formatMilitaryTime(entity.timeWindow.startTime) +
+          //     ' - ' +
+          //     formatMilitaryTime(entity.timeWindow.endTime)
+          // }
           return entity
         })
         console.debug(loaddedShifts)
diff --git a/src/features/userAssignment/tables/AvailableUsersTable.tsx b/src/features/userAssignment/tables/AvailableUsersTable.tsx
index 08e93e3..6c6c8fb 100644
--- a/src/features/userAssignment/tables/AvailableUsersTable.tsx
+++ b/src/features/userAssignment/tables/AvailableUsersTable.tsx
@@ -18,6 +18,7 @@ import { RootState } from '@/store/store'
 import SortedTable from '@/components/shared/tables/SortedTable'
 import { selectSelectedUserId, setSelectedUserId } from '../userAssignmentSlice'
 import { selectCurrentHouse } from '@/features/auth/authSlice'
+import { createListOfUsersForShift } from '@/sprintFiles/availabilityHelper'
 
 type AvailableUsersTableProps = {
   day: string
@@ -107,7 +108,7 @@ const AvailableUsersTable: React.FC<AvailableUsersTableProps> = ({
 
   // define state variables
   const authHouse = useSelector(selectCurrentHouse) as House
-  const [listOfUserIds, setLitsOfUserIds] = useState<EntityId[]>([])
+  const [listOfUserIds, setListOfUserIds] = useState<EntityId[]>([])
   const [disableTable, setDisableTable] = useState(
     selectedUserId ? true : false
   )
@@ -157,10 +158,24 @@ const AvailableUsersTable: React.FC<AvailableUsersTableProps> = ({
   useEffect(() => {
     // would filter the userIds here, but not doing any filtering or sorting right now
     if (isUsersDataSuccess && usersData) {
-      let userIds = usersData.ids
-      setLitsOfUserIds(userIds)
+      let days = []
+      if (day === 'All') {
+        days = [
+          'Sunday',
+          'Monday',
+          'Tuesday',
+          'Wednesday',
+          'Thursday',
+          'Friday',
+          'Saturday',
+        ]
+      } else {
+        days = [day]
+      }
+      let userIds = createListOfUsersForShift(shiftObject, usersData, days)
+      setListOfUserIds(userIds)
     }
-  }, [isUsersDataSuccess, usersData])
+  }, [day, isUsersDataSuccess, shiftObject, usersData])
 
   useEffect(() => {
     if (selectedUserId) {
diff --git a/src/pages/account/testing/ShiftAssignmentHelper.tsx b/src/pages/account/testing/ShiftAssignmentHelper.tsx
new file mode 100644
index 0000000..322837c
--- /dev/null
+++ b/src/pages/account/testing/ShiftAssignmentHelper.tsx
@@ -0,0 +1,58 @@
+import { useGetUsersQuery } from "@/features/user/userApiSlice";
+import { createListOfUsersForShift } from "@/sprintFiles/availabilityHelper";
+import { useEffect } from "react";
+
+const ShiftAssignmentHelper = () => {
+    const {
+        data: dataUsers,
+        isLoading,
+        isSuccess,
+        isError,
+        error,
+    } = useGetUsersQuery({})
+
+    const testFunction = () => {
+        let testShiftObject = {
+            id: "1",
+            name: "Clean the house",
+            shiftID: "4iWhGXXz65H0aPfaF3RJ",
+            description: "Clean house pls ggreg sucks", 
+            possibleDays: ["Monday", "Tuesday", "Wednesday"],
+            timeWindow: {
+                startTime: "1930",
+                endTime: "2300"
+            },
+            timeWindowDisplay: "",
+            assignedDay: "",
+            assignedUser: "maybe populate this with user id",
+            hours: 1.5,
+            verificationBuffer: 1,
+            verification: false,
+            category: "hehe",
+            preferences: {
+                preferredBy: [""],
+                dislikedBy: [""]
+            }
+        }
+        
+        let testDays = ["Sunday", "Monday"];
+        if (dataUsers !== undefined) {
+            console.log(createListOfUsersForShift(testShiftObject, dataUsers, testDays));
+        }
+        
+        // console.log(dayjs('1900', 'HHmm').format('HHmm'))
+        // const num = 1900
+        // console.log(dayjs(num.toString(), 'HHmm'))        
+    }
+
+    useEffect(() => {
+        testFunction();
+    }, [dataUsers])
+    return (
+        <div>
+            hello
+        </div>
+    )
+}
+
+export default ShiftAssignmentHelper
\ No newline at end of file
diff --git a/src/sprintFiles/availabilityHelper.ts b/src/sprintFiles/availabilityHelper.ts
new file mode 100644
index 0000000..04a5dcc
--- /dev/null
+++ b/src/sprintFiles/availabilityHelper.ts
@@ -0,0 +1,181 @@
+import { Dictionary, EntityId, EntityState } from "@reduxjs/toolkit";
+import {Shift, User} from "../types/schema";
+import dayjs, { Dayjs } from "dayjs";
+import { HOURS_REQUIRED, NEUTRAL_PREFERENCE, LIKED_PREFERENCE, DISLIKED_PREFERENCE } from "@/utils/constants";
+
+// TODO: DOESN'T WORK IF SOMEONE IS ALREADY ASSIGNED DURING THEIR AVAILABILITY PERIOD TO A DIFFERENT SHIFT
+
+/**
+ * Returns a list of user ids that are available to complete the shift
+ *
+ * @param shiftObject - The shift object
+ * @param days - The days that we iterate through
+ * @param entityState - the entity state from redux
+ * @returns A list of user ids that are available to complete the shift
+*/
+const filterUsersByAvailability = (shiftObject: Shift, days: string[], entityState: EntityState<User>) => {
+  const numHours = Math.floor(shiftObject.hours);
+  const numMinutes = (shiftObject.hours - numHours) * 60;
+  const shiftStart: Dayjs = dayjs(shiftObject.timeWindow.startTime, 'HHmm')
+  const shiftEnd: Dayjs = dayjs(shiftObject.timeWindow.endTime, 'HHmm')
+  const shiftID = shiftObject.shiftID;
+  let totalUsersInHouse: EntityId[] = entityState.ids;
+  let availableUserIDs: EntityId[] = [];
+  let idToObjectDictionary: Dictionary<User> = entityState.entities;
+  // iterate thru all users in the house
+  for (let i = 0; i < totalUsersInHouse.length; i++) {
+    const userID = totalUsersInHouse[i];
+    const userObject = idToObjectDictionary[userID];
+    if (userObject === undefined) {
+        continue;
+    }
+    // if this user has already been assigned to this shift, display them regardless of hours
+    if (userObject.assignedScheduledShifts !== undefined && userObject.assignedScheduledShifts.includes(shiftID)) {
+        availableUserIDs.push(userID)
+        continue;
+    }
+    const currAvailabilities: { [key: string]: { startTime: string; endTime: string }[] } = userObject.availabilities;
+    if (currAvailabilities === undefined) {
+        continue;
+    }
+    // flag to determine if user id has been added to the list of available user ids already so that we only add a user id to the list once
+    let isAdded = false;
+    // iterate thru all days for a user
+    for (let j = 0; j < days.length; j++) {
+        const day = days[j];
+        if (!(day.toLowerCase() in currAvailabilities)) {
+            continue;
+        }
+
+        const perDayAvailability = currAvailabilities[day.toLowerCase()];
+        if (perDayAvailability === undefined) {
+            continue;
+        }
+        // iterate thru all availabilities per day for a user
+        // TODO: CHECK IF THEYRE ASSIGNED TO A DIFFERENT SHIFT DURING THE AVAILABILITY WINDOW
+        for (let k = 0; k < perDayAvailability.length; k++) {
+            const currInterval = perDayAvailability[k];
+            // start of the user availability window
+            let userStart: Dayjs = dayjs("" + currInterval.startTime, 'HHmm')
+            // end of the user availability window
+            let userEnd: Dayjs = dayjs("" + currInterval.endTime, 'HHmm')
+            // if user's availability window ends before the start of the shift, can continue
+            if (userEnd.isBefore(shiftStart) || userEnd.isSame(shiftStart)) {
+                continue;
+            }
+            // calculatedStart = either the start of the shift or the start of the user's availability, whichever comes later
+
+            let calculatedStart: Dayjs = shiftStart;
+            if (userStart.isAfter(shiftStart)) {
+                calculatedStart = userStart;
+            }
+            // add the number of hours required to complete to the calculatedStart
+            const calculatedEnd = calculatedStart.add(numHours, 'hour').add(numMinutes, 'minute');
+            // calculatedEndRequirement = either the end of the shift or the end of the user's availability, whichever comes earlier
+            let calculatedEndRequirement: Dayjs = shiftEnd;
+            if (userEnd.isBefore(shiftEnd)) {
+                calculatedEndRequirement = userEnd;
+            }
+            // only add the user id if the calculated end of when they would finish the shift is before the end of the shift or the end of their availability, whichever comes first
+            if (calculatedEnd.isBefore(calculatedEndRequirement) || calculatedEnd.isSame(calculatedEndRequirement)) {
+                availableUserIDs.push(userID);
+                isAdded = true;
+                break;
+            }
+        }
+        if (isAdded) {
+            break;
+        }
+    }
+  }
+  return availableUserIDs;
+}
+
+/**
+ * Returns a list of user ids that are eligible to complete the shift (hours unassigned >= credit hours/already assigned to the shift)
+ *
+ * @param ids - A list of user entity ids
+ * @param entityState - the entity state from redux
+ * @param creditHours - the credit hours for the shift
+ * @param shiftID - the id of the shift
+ * @returns A list of user ids that are eligible to complete the shift
+*/
+const filterUsersByEligibility = (ids: EntityId[], entityState: EntityState<User>, creditHours: number, shiftID: string) => {
+    const eligibleIDs: EntityId[] = [];
+    const idToObjectDictionary: Dictionary<User> = entityState.entities;
+    for (let i = 0; i < ids.length; i++) {
+        const id = ids[i];
+        const userObject = idToObjectDictionary[id];
+        if (userObject === undefined) {
+            continue;
+        }
+        // put the assigned user in eligibleIDs, regardless
+        if (userObject.assignedScheduledShifts !== undefined && userObject.assignedScheduledShifts.includes(shiftID)) {
+            eligibleIDs.push(id)
+            continue;
+        }
+        // push them on the list if the hours they need >= creditHours
+        const assignableHours: number = HOURS_REQUIRED - userObject.hoursAssigned;
+        if (assignableHours >= creditHours) {
+            eligibleIDs.push(id);
+        }
+    }
+    return eligibleIDs;
+}
+
+/**
+ * Returns a list of user ids that are sorted, first on whether they prefer the shift and second as a tiebreaker on the number of unassigned hours (higher is higher priority)
+ *
+ * @param shiftObject - The shift object
+ * @param ids - The list of entity ids
+ * @param entityState - the entity state from redux
+ * @returns A sorted list of the entity ids that are passed in
+*/
+const sortUsersByNeededHoursAndPreference = (ids: EntityId[], entityState: EntityState<User>, shiftObject: Shift) => {
+    const idToObjectDictionary: Dictionary<User> = entityState.entities;
+    const likedList = shiftObject.preferences.preferredBy;
+    const dislikedList = shiftObject.preferences.dislikedBy;
+    const sorted = ids.sort((id1, id2) => {
+        const user1 = idToObjectDictionary[id1];
+        const user2 = idToObjectDictionary[id2];
+        if (user1 === undefined || user2 === undefined) {
+          return 0;
+        }
+        // First sort on preferences
+        let user1Preference = NEUTRAL_PREFERENCE;
+        if (likedList.includes("" + id1)) {;
+            user1Preference = LIKED_PREFERENCE;
+        } else if (dislikedList.includes("" + id1)) {
+            user1Preference = DISLIKED_PREFERENCE;
+        }
+        let user2Preference = NEUTRAL_PREFERENCE;
+        if (likedList.includes("" + id2)) {
+            user2Preference = LIKED_PREFERENCE;
+        } else if (dislikedList.includes("" + id2)) {
+            user2Preference = DISLIKED_PREFERENCE;
+        }
+        if (user2Preference - user1Preference != 0) {
+            return user2Preference - user1Preference;
+        }
+        // Second sort on hours assignable leftr, prioritizing people with higher preferences (user2 - user1)
+        const user1HoursLeft = HOURS_REQUIRED - user1.hoursAssigned
+        const user2HoursLeft = HOURS_REQUIRED - user2.hoursAssigned
+        return user2HoursLeft - user1HoursLeft;
+    })
+    return sorted;
+}
+
+/**
+ * Returns a list of user ids that are available and eligible to complete the shift; returns it in sorted order
+ *
+ * @param shiftObject - The shift object
+ * @param days - The days that we iterate through
+ * @param entityState - the entity state from redux
+ * @returns A list of user ids that are available and eligible to complete the shift; returns it in sorted order
+*/
+export const createListOfUsersForShift = (shiftObject: Shift, entityState: EntityState<User>, days: string[]) => { 
+    const availableIDs = filterUsersByAvailability(shiftObject, days, entityState);
+    const availableAndEligibleIDs = filterUsersByEligibility(availableIDs, entityState, shiftObject.hours, shiftObject.shiftID);
+    const sortedAvailableAndEligibleIDs = sortUsersByNeededHoursAndPreference(availableAndEligibleIDs, entityState, shiftObject);
+    return sortedAvailableAndEligibleIDs;
+}
\ No newline at end of file
diff --git a/src/types/schema.ts b/src/types/schema.ts
index 3e1e63f..6b27bb5 100644
--- a/src/types/schema.ts
+++ b/src/types/schema.ts
@@ -71,7 +71,7 @@ export type Shift = {
   // Possible days that the shift can be done on
   possibleDays: string[]
   // Time window that this shift must be done in [startTime, endTime]
-  timeWindow: { startTime: number; endTime: number }
+  timeWindow: { startTime: string; endTime: string }
   // property to display timeWindow
   timeWindowDisplay: string //Todo: Maybe delete this property
   // Day that the shift is assigned
diff --git a/src/utils/constants.ts b/src/utils/constants.ts
index bf1cf4e..4a5ba12 100644
--- a/src/utils/constants.ts
+++ b/src/utils/constants.ts
@@ -109,4 +109,9 @@ export const DAYS = [
   'thursday',
   'friday',
   'saturday',
-]
\ No newline at end of file
+]
+
+export const HOURS_REQUIRED = 5;
+export const NEUTRAL_PREFERENCE = 1;
+export const LIKED_PREFERENCE = 2;
+export const DISLIKED_PREFERENCE = 0;
\ No newline at end of file