zulip/templates/zerver/help/change-the-date-and-time-format.md

Change the date and time format

By default, messages in Zulip are displayed with a 12-hour timestamp. If you are used to seeing time displayed in a 24-hour format, you can change the Zulip timestamp format from a 12-hour format to a 24-hour format. You may want to do this to avoid confusion between A.M. and P.M. hours.

You can easily change the date and time format your messages are displayed in by following a few steps.

{!go-to-the.md!} Display Settings {!settings.md!}

2. Select the option labeled Display time in 24-hour format (17:00 instead of 5:00 PM), then reload the page in order for the change to take effect.