How to Change Vista Clock Display from 24hr to 12hr?


Time is displayed in two formats – 24hrs and 12hrs. For example after 12:59, either 13:00 (24hrs format) or 1:00 (12hrs format) is displayed. If you are using default settings for the United States, system will have 12-hour clock settings and for other countries/regions use 24-hour clock.

Here are simple steps to change or switch between 24hr and 12hr clock settings on your Windows Vista computer:

1. Click the Start button.
2. Click Control Panel, click Clock, Language and Region. If you are using Control Panel in Classic View, double-click Regional and Language Options, and then skip the next step.
3. Click Regional and Language Options.
4. Click Customize this format.
5. On the Time tab, do one of the following:

  • Change Time format to HH:mm:ss for a 24-hour clock.
  • Change Time format to hh:mm:ss tt for a 12-hour clock.

Windows XP also use similar settings for clock display. In Control Panel, click Date, Time, Language, and Regional Options. Click Regional and Language Options > Customize > Time tab and then change the time format.

QuickTip: Microsoft Outlook shows time as 13:00PM and not 1:00PM. You don’t have to modify any settings in Outlook, instead switch system display clock format using above procedure to configure time format.



  1. Amazing that this stuff is squirreled away in such an obscure place. And I am considered a computer expert!!! Couldn’t find this without coming here. Thanks.

  2. razeem a r says

    thank you so much

  3. Thanks!!! I prefer 24hour clock!

  4. thanks a lot……….

  5. TY …

  6. Thx – this was driving me nutz, what a relief. No way to find out unless u come across a site like this ….

  7. Thanks a lot.. I am new to Windows 7 and was not able to figure this out. this page really helped

  8. Napsterabhi says

    thnx……………u did g8 help to me………….

  9. Grant Kozlak says

    Thanks! The only thing is I want my clock in 24 hr, not 12 hr format. And I am using Windows 7, not vista. Anyways, thanks and I always come back here if I need to!

  10. hi iam new 2 vista can u help me how 2 change background on my removeable fortable device(pen drive)

  11. awesome really helped out thnx

  12. Thanx greatly for this. It was bugging me.

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  16. thx man!!!

  17. nick plunkett says

    Thanks for this, it really helped me as I am new to vista and just couldn’t figure out how to change the clock over.

  18. Mohammed Arif says

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