How to change the first day of the week in the iPhone Calendar

In short

Open Settings, tap Apps, then Calendar, scroll down and tap Start Week On. Tap a weekday under Calendar App Only. On our iPhone 17e the tick was on System Setting, which follows the region set under Language & Region.

6 of 6 steps show a real screenshot from our iPhone 17e.

Steps

1. 1

   Open Settings and tap Apps

   Scroll down and tap Apps.

   On our iPhone 17e it is in its own group below Game Center, iCloud and Wallet & Apple Pay.

   Done
   
2. 2

   Tap Calendar

   The apps are in alphabetical order.

   On our iPhone 17e Calendar is the second row under C, after Calculator.

   Done
   
3. 3

   Scroll down and tap Start Week On

   It is further down the page than Week Numbers and Week View Starts On Today, below Duration for New Events and above Default Calendar.

   Done
   
4. 4

   See what is selected now

   The tick is on System Setting, under Mirror System Setting, with the region's first day in brackets. On our iPhone 17e it read System Setting (Monday).

   The note below says the Calendar then uses the setting from Language & Region.

   Done
   
5. 5

   Tap the day you want

   Choose any day from Sunday to Saturday under Calendar App Only. The note at the bottom says the choice applies in Calendar only, and other apps keep the system setting.

   On our iPhone 17e, when we tapped Wednesday, the tick moved there and left System Setting.

   Done
   
6. 6

   Check the result in Calendar

   Open the Calendar app and tap a day.

   On our iPhone 17e, with Wednesday picked, the week strip at the top of the day view started on Wednesday: W T F S S M T, from 7 to 13 October.

   Language & Region still showed First Day of Week: Monday, so other apps kept Monday. We set Calendar back to System Setting afterwards.

   Done
   

If you do not see this option

• You are looking in the Calendar app. The choice is in the Settings app. Apple's iOS 26 and iOS 27 guides both give the path Settings, Apps, Calendar, Start Week On. Sources: Change your Calendar settings on iPhone, Change your Calendar settings on iPhone (iOS 26)
• You are on iOS 26. Apple's iOS 26 guide gives the same path: Settings, Apps, Calendar, Start Week On. Sources: Change your Calendar settings on iPhone, Change your Calendar settings on iPhone (iOS 26)

If this does not work

• Other apps still start the week on the old day. Don't worry, nothing went wrong. The choice under Calendar App Only applies in Calendar only, as the note on the page says. On our iPhone 17e, with Wednesday picked, Language & Region still showed Monday. To change it for the whole phone, tap the blue Language & Region link on the Start Week On page.
• Week view starts on today instead. According to Apple, Week View Starts On Today on the Calendar settings page shows the current day as the first day in Week view. On our iPhone 17e it was off.

Good to know

However, if you want the change everywhere and not just in Calendar, tap the blue Language & Region link on the Start Week On page. That changes the first day for every app.

You may also notice Week View Starts On Today, on the Calendar settings page, which makes Week view start on the current day instead. It was off on our iPhone 17e.

Week numbers are on the same Calendar page too: how to show week numbers in the Calendar on an iPhone.

Apple's iPhone User Guide for iOS 27 gives the same route, Settings, Apps, Calendar, then Start Week On, and lists it with Week Numbers, Week View Starts On Today and Alternate Calendars on the same page.

Two more Calendar settings: adding a holiday calendar, so public holidays show in your weeks, and setting default alert times for events.

Watch these steps

Watch on YouTubeThe same steps, recorded on our iPhone 17e · opens YouTube

About this guide

Device

iPhone

Shown on

iOS 27.0.1 (iPhone 17e)

App

Settings

Path

Settings › Apps › Calendar › Start Week On

Real screenshots

6 of 6 steps

Checked

October 2026

Sources

2 official, linked below

What changed: the screenshots are now our own iPhone 17e on iOS 27.0.1, dark mode, and the wording is checked against those screens and Apple's iOS 27 guide.

Sources

• Apple Support: Change your Calendar settings on iPhone
• Apple iPhone User Guide: Change your Calendar settings on iPhone (iOS 26)

Links checked October 2026. Menus and features can change with updates.

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