diff --git a/app/Http/Controllers/OvertimeTimesheetController.php b/app/Http/Controllers/OvertimeTimesheetController.php
index 616f2e06..bf5af6bc 100644
--- a/app/Http/Controllers/OvertimeTimesheetController.php
+++ b/app/Http/Controllers/OvertimeTimesheetController.php
@@ -18,7 +18,7 @@ public function __invoke(?string $month = null): BinaryFileResponse
         $this->authorize("manageRequestsAsAdministrativeApprover");
 
         $month = Carbon::canBeCreatedFromFormat($month, "m-Y")
-            ? Carbon::createFromFormat("m-Y", $month)
+            ? Carbon::createFromFormat("d-m-Y", "01-$month")
             : Carbon::now();
 
         $users = User::query()
diff --git a/app/Http/Controllers/TimesheetController.php b/app/Http/Controllers/TimesheetController.php
index a1956238..8b401339 100644
--- a/app/Http/Controllers/TimesheetController.php
+++ b/app/Http/Controllers/TimesheetController.php
@@ -20,7 +20,7 @@ public function __invoke(VacationTypeConfigRetriever $configRetriever, ?string $
         $this->authorize("manageRequestsAsAdministrativeApprover");
 
         $month = Carbon::canBeCreatedFromFormat($month, "m-Y")
-            ? Carbon::createFromFormat("m-Y", $month)
+            ? Carbon::createFromFormat("d-m-Y", "01-$month")
             : Carbon::now();
 
         $users = User::query()
diff --git a/app/Http/Controllers/VacationCalendarController.php b/app/Http/Controllers/VacationCalendarController.php
index 0a7e8cb1..f896614b 100644
--- a/app/Http/Controllers/VacationCalendarController.php
+++ b/app/Http/Controllers/VacationCalendarController.php
@@ -22,7 +22,7 @@ public function index(
         ?string $month = null,
     ): Response|RedirectResponse {
         $month = Carbon::canBeCreatedFromFormat($month, "m-Y")
-            ? Carbon::createFromFormat("m-Y", $month)
+            ? Carbon::createFromFormat("d-m-Y", "01-$month")
             : Carbon::now();
 
         /** @var User $currentUser */