I have my laptop, running Windows 10, set to English United States region, my O365 site region is set to United States, all excel formatting is set to display dates in US format mm/dd/yyyy, however all my online excel files will only allow entry in UK formats and switches them to US display format.

e.g. if want to enter 23rd April 2018, I must enter 23/4/18 in order for it to display 4/23/18. Any dates entered as us 4/23/18 get rejected as invalid dates.

This is not a formatting issue as I can clearly see the cell formatting is set to US date format mm/dd/yy.

Does anyone know how to truly set the region of an O365 excel document?

1 Answer 1


The regional settings for Excel online will be determined by the online host, i.e. OneDrive for Business or SharePoint, not by Excel.

In OneDrive for Business, click the cog wheel at the top right, then Site Settings > Regional settings.

Confirm that both the Time Zone AND the Region Locale are set to US time zone and English (United States) respectively. If you need to make changes, be sure to click OK at the bottom of the page.

I've just tested this in O4B and the Region Locale is the factor that determines Excel Online's date display.

The same goes for SharePoint online. If you don't have permissions to change the settings, ask the site owner to do it.

  • Thanks for the suggestion, I am the site owner however I confirm that both the Time and Region are set to US, yet am still only allowed UK entry. Apr 17, 2018 at 10:07
  • Does that happen with EVERY Excel file or just a specific one?
    – teylyn
    Apr 17, 2018 at 11:13

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