diff --git a/frontend/src/views/admin/PromoCodesView.vue b/frontend/src/views/admin/PromoCodesView.vue
index ceca0dd4e8..34cc9ef94b 100644
--- a/frontend/src/views/admin/PromoCodesView.vue
+++ b/frontend/src/views/admin/PromoCodesView.vue
@@ -392,7 +392,7 @@ import { useAppStore } from '@/stores/app'
 import { useClipboard } from '@/composables/useClipboard'
 import { getPersistedPageSize } from '@/composables/usePersistedPageSize'
 import { adminAPI } from '@/api/admin'
-import { formatDateTime } from '@/utils/format'
+import { formatDateTime, formatDateTimeLocalInput } from '@/utils/format'
 import type { PromoCode, PromoCodeUsage } from '@/types'
 import type { Column } from '@/components/common/types'
 import AppLayout from '@/components/layout/AppLayout.vue'
@@ -628,7 +628,9 @@ const handleEdit = (code: PromoCode) => {
   editForm.bonus_amount = code.bonus_amount
   editForm.max_uses = code.max_uses
   editForm.status = code.status
-  editForm.expires_at_str = code.expires_at ? new Date(code.expires_at).toISOString().slice(0, 16) : ''
+  editForm.expires_at_str = code.expires_at
+    ? formatDateTimeLocalInput(Math.floor(new Date(code.expires_at).getTime() / 1000))
+    : ''
   editForm.notes = code.notes || ''
   showEditDialog.value = true
 }