diff --git a/packages/backend/src/server/api/endpoints/notes/create.ts b/packages/backend/src/server/api/endpoints/notes/create.ts
index 20f1cfd4e7..3655fba23a 100644
--- a/packages/backend/src/server/api/endpoints/notes/create.ts
+++ b/packages/backend/src/server/api/endpoints/notes/create.ts
@@ -202,7 +202,7 @@ export const paramDef = {
 			type: 'object',
 			nullable: true,
 			properties: {
-				scheduledAt: { type: 'integer', nullable: false },
+				scheduledAt: { type: 'string', nullable: false },
 			},
 		},
 	},
diff --git a/packages/frontend/src/components/MkPostForm.vue b/packages/frontend/src/components/MkPostForm.vue
index 8f0737b146..804bdbe49a 100644
--- a/packages/frontend/src/components/MkPostForm.vue
+++ b/packages/frontend/src/components/MkPostForm.vue
@@ -775,10 +775,6 @@ async function post(ev?: MouseEvent) {
 		}
 	}
 
-	if (postData.schedule?.scheduledAt && typeof postData.schedule.scheduledAt === 'string') {
-		postData.schedule.scheduledAt = parseInt(postData.schedule.scheduledAt);
-	}
-
 	let token = undefined;
 
 	if (postAccount) {
diff --git a/packages/frontend/src/components/MkScheduleEditor.vue b/packages/frontend/src/components/MkScheduleEditor.vue
index f6336ddf69..b5083ad050 100644
--- a/packages/frontend/src/components/MkScheduleEditor.vue
+++ b/packages/frontend/src/components/MkScheduleEditor.vue
@@ -43,12 +43,12 @@ if ( props.modelValue && props.modelValue.scheduledAt) {
 
 function get() {
 	const calcAt = () => {
-		return new Date(`${atDate.value} ${atTime.value}`).getTime();
+		return new Date(`${atDate.value}T${atTime.value}`).toISOString();
 	};
 
 	return {
 		...(
-			props.modelValue ? { scheduledAt: calcAt() } : {}
+			props.modelValue ? { scheduledAt: calcAt() } : ''
 		),
 	};
 }