diff --git a/db/booking.ts b/db/booking.ts
index 4555453..34d738a 100644
--- a/db/booking.ts
+++ b/db/booking.ts
@@ -16,10 +16,12 @@ export type Booking = {
   zip: string
   city: string
   bill?: Bill
-  start: string
+  // format YYYY-MM-DD
+  start: string,
   startDate: Date
-  endDate: Date
+  // format YYYY-MM-DD
   end: string
+  endDate: Date
   status?: BOOKING_STATUS
   purpose?: string
   org?: string
diff --git a/helpers/booking.ts b/helpers/booking.ts
index 981297f..951a804 100644
--- a/helpers/booking.ts
+++ b/helpers/booking.ts
@@ -1,6 +1,20 @@
+import { BookFormData } from '../context/book'
 import { BOOKING_STATUS } from '../db/enums'
+import { dateFormatBackend } from './date';
 import fetch from './fetch'
 
+function getBody(formData: BookFormData) {
+  const body: any = {
+    ...formData,
+  };
+
+  // if existend, convert dates to TZ less YYYY-MM-DD format
+  body.startDate && (body.startDate = dateFormatBackend(body.startDate))
+  body.endDate && (body.endDate = dateFormatBackend(body.endDate))
+
+  return body;
+}
+
 export function getBookingStatus(status: BOOKING_STATUS) {
   switch (status) {
     case BOOKING_STATUS.REQUESTED:
@@ -16,10 +30,10 @@ export function getBookingStatus(status: BOOKING_STATUS) {
   }
 }
 
-export async function createBooking(formData: object) {
+export async function createBooking(formData: BookFormData) {
   return fetch('/api/bookings', {
     method: 'POST',
-    body: formData,
+    body: getBody(formData),
   })
 }
 
@@ -30,9 +44,9 @@ export async function cancelBooking(uuid: string) {
   })
 }
 
-export async function patchBooking(uuid: string, bookingData: object) {
+export async function patchBooking(uuid: string, bookingData: BookFormData) {
   return fetch(`/api/bookings/${uuid}`, {
     method: 'PATCH',
-    body: { ...bookingData },
+    body: getBody(bookingData),
   })
 }