I did a quick search @Doagy using the search bar above and found many eh k posts.
You also might want to click on help that's found below.. There you will find your user manual and online interactive guide
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Fitbit Product Experts Alumni are retired members of the Fitbit Product Expert Program. Learn more
You can choose between 12 and 24 hour clocks in your profile settings at https://www.fitbit.com/user/profile/edit
Once changed and saved the next time you sync your fitbit will be updated
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