How to change the first day of the week in the iPhone Calendar (iPhone 17e, iOS 27)

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.

howtosimply.com/guides/how-to-change-the-first-day-of-the-week-in-the-iphone-calendar/ · Checked October 2026 · iPhone 17e · iOS 27.0.1

If you do not see this option

• You are looking in the Calendar app. The choice is in the Settings app, not in Calendar. Apple's iOS 26 and iOS 27 guides both give the path Settings, Apps, Calendar, Start Week On. Source: Change your Calendar settings on iPhone · Source: 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. Source: Change your Calendar settings on iPhone · Source: Change your Calendar settings on iPhone (iOS 26)

6 of 6 steps with real screenshots · 2 official sources below

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

Step by step

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.

   Watch these steps Done

2. 

   Tap Calendar

   The apps are in alphabetical order.

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

   Done

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. 

   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. 

   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. 

   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

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.

Watch these steps

If this does not work

• Other apps still start the week on the old day. 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. Switch it off if you want Week view to follow Start Week On. On our iPhone 17e it was off. Source: Change your Calendar settings on iPhone · Source: Change your Calendar settings on iPhone (iOS 26)

About this guide

Whether a week starts on Sunday or Monday depends on the region the iPhone is set to. If the Calendar shows the wrong first day for you, you can change it for the Calendar alone, without changing the region of the whole phone.

Screenshots: iPhone 17e, iOS 27.0.1, dark mode.

Good to know

To change the first day for every app, tap the blue Language & Region link on the Start Week On page.

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

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

In short: Settings, Apps, Calendar, Start Week On, tap a day.