Your Outlook calendar may show Sunday as the first day of the week when you prefer Monday. This happens because Outlook uses your Windows regional settings to determine the week layout. The calendar view in the main window and the Date Navigator will both reflect this setting.
This article explains why the week start day changes and provides the steps to set it to Monday. You will learn how to adjust the setting within Outlook and verify the corresponding Windows configuration.
Key Takeaways: Setting Your Calendar Week to Start on Monday
- File > Options > Calendar > Work time: This menu controls the first day of the week displayed in your Outlook calendar views.
- Windows Settings > Time & Language > Region: The Windows regional format setting is the primary source for Outlook’s week start day.
- Date Navigator: The small monthly calendar in the folder pane updates immediately after you change the First day of week setting.
How Outlook Determines the First Day of the Week
Outlook does not have an independent setting for the week’s start. It pulls this information directly from your operating system’s regional and language options. This design ensures consistency across Microsoft 365 applications and Windows itself.
The setting affects all calendar views, including Day, Week, and Month. It also controls the layout of the Date Navigator, the small monthly calendars in the folder pane. If your calendar shows Sunday but your region uses Monday, the configuration likely needs correction in Windows.
Prerequisites for Changing the Setting
You need a working Outlook profile connected to an email account. The steps are identical for Microsoft 365, Outlook 2021, and Outlook 2019. You must have permission to change settings on your Windows PC, as the primary fix involves system-level regional formats.
Steps to Set Your Calendar Week to Start on Monday
Follow these steps to change the first day of the week in your Outlook calendar. Start with the Outlook application setting, then verify the Windows configuration.
- Open Outlook Options
Launch Outlook and click File in the top-left corner. Select Options from the left-hand menu to open the Outlook Options dialog box. - Navigate to Calendar Settings
In the Outlook Options window, click the Calendar category on the left. This opens settings related to your calendar display and work hours. - Adjust the Work Time Settings
Scroll to the Work time section. Locate the dropdown menu labeled First day of week. Click the dropdown and select Monday from the list. Click OK at the bottom of the window to save and apply the change. - Verify the Change in Calendar View
Return to your main Outlook window and switch to the Calendar module. Change your view to Week or Month. The week should now begin with Monday. Check the Date Navigator in the folder pane to confirm.
If the Outlook Setting Does Not Stick
If the calendar reverts to Sunday or the Monday option is unavailable, you must change the Windows regional setting. This is the master setting that Outlook uses.
- Open Windows Settings
Click the Start menu and select the Settings gear icon. Alternatively, press Windows key + I on your keyboard to open Settings directly. - Go to Time & Language Settings
In the Settings window, click Time & Language. Then, select the Region tab from the left-side menu in Windows 11. In Windows 10, this tab is called Region & language. - Modify Regional Format
Find the section labeled Regional format. Click the dropdown menu or the Change data formats button. Look for the setting named First day of week. Change this value to Monday. Close the Settings window. - Restart Outlook
Close and restart Outlook completely for the new Windows regional setting to take effect. Your calendar week should now correctly start on Monday.
Common Mistakes and Limitations
Outlook Web App Shows a Different First Day
Outlook on the web uses its own independent setting. To change it, click the Settings gear icon, view all settings, and go to Calendar > View. Adjust the First day of week option there. This setting does not sync with the desktop Outlook application.
Calendar Printing Uses the Old Setting
If you print a calendar, the print preview might still show Sunday. Ensure you have applied the change in both Outlook and Windows, then restart the application. Use the Print Options dialog to select a specific date range that aligns with your new Monday-start week.
Shared Calendars Appear Unchanged
The week start day is a per-user view setting. Changing it on your computer only affects how you see calendar data. Other people sharing their calendar with you will not see your change, and their view remains controlled by their own settings.
Outlook Setting vs Windows Setting: Key Differences
| Item | Outlook Calendar Option | Windows Regional Format |
|---|---|---|
| Primary Function | Overrides the view within Outlook temporarily | System-wide master setting for all apps |
| Scope of Change | Only affects the Outlook desktop application | Affects Outlook, Taskbar calendar, and other programs |
| Persistence | Can revert if Windows setting conflicts | Definitive and controls the Outlook option |
| Access Path | File > Options > Calendar > Work time | Windows Settings > Time & Language > Region |
You can now set your Outlook calendar to begin the week on Monday. First, check the setting in Outlook under Calendar options. If the change does not apply, configure the First day of week in your Windows regional formats. For a related adjustment, explore the Work hours settings in the same Calendar options menu to define your business day. An advanced tip is to use the Windows command control intl.cpl to open the legacy Region control panel for more detailed format editing.