iCal Missing AM/PM Option? Change to 24-hour Mode!

Am I crazy or is there no way to make iCal show AM/PM when editing a calendar entry?

iCal Missing AM/PM Option

The AM/PM option IS there, because if I use the arrow key to move over to next field, there's a hidden AM/PM field which I can change. However, unless I know what it's already set to, I have no way of knowing what I'm changing it to. Very annoying.

My fix for this is to simply use 24-hour mode, which I already use on my main system clock anyway. (By the way, if you have trouble converting 24-hour time to 12-hour time, you might want to check out my post on Learning to Interpret Military Time.) Unfortunately, enabling the "Use a 24-hour clock" option in the Date & Time settings does not enable 24-hour clock mode in iCal. To do this, you must modify the International settings (!?).

System Preferences -> International -> Formats -> Times -> Customize

Changing time format

From here, you can select and delete the AM/PM option from the white field and then click the little arrow on the hour field to change it's format to 24-hour (this screen is very non-intuitive for something made by Apple). I made the changes to Short, Medium, Long, and Full time formats and then clicked OK and WHAM! iCal showed 24-hour time and made it possible to easily change the time on an entry.

iCal 24-hour format

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  1. Thanks, it is one of the first thing that I see from apple that is really difficult to set up. I could not made it without your guide. Thanks a lot.

  2. Thanks, that helped. I was stuck with AM/PM which is so unintuitive for a european. We don’t use that. EVER.

  3. K,

    I don’t use AM/PM either… I find 24-hour time to be so much more intuitive! I also prefer my dates to be written like YYYY-MM-DD HH:MM:SS (e.g., 2008-11-03 16:34:02), since that easily represents greatest to least measurement of time from left to right. 🙂

  4. Thanks for a solution that has been bugging me for months.

    I am retired military and can state that the whole of the US should go to 24 hour clock. It solves so many mistakes and misunderstandings!

  5. Walt, I totally agree with you! Moving to a 24 hour clock makes a lot of sense and would simplify so many things. The ISO 8601 standard is a great guide to writing dates and times in an easily understood format.

  6. Thanks very much, was finding it tricky myself. As you say not very intuitive for an Apple-designed app.
    Anyway, sorted!

  7. Raam,
    New to Apple. Trying to set up my iCal 3.0.7 I find Preferences under the iCal column but not the
    System Preferences -> International -> Formats -> Times -> Customize route that you show. Where to I find this? thanks for any help.

  8. Thank you! I didn’t realize that I had to change all those options to make it work. It was driving me crazy why I couldn’t type in 9 or 09 to get the morning hour and it kept showing 21. Fixed now!

  9. My husband and I thank you very much! Wanted to let you know that we found our change in “Language & Text” > “Formats” > “Times”. We are running OS X 10.6.2.

    • You’re welcome, KM! I wish I could make this solution more easily available to those looking for it! I remember how frustrated I was and it wasn’t fun!

      Thanks for stopping by. 🙂

  10. Like much in life, it is simple…
    once you know how!
    Thank you for a great tip.
    Now, how about a tip to add ISO 8601 numerical calendar weeks?

    • Hi Tygerklaw,

      I’m glad you found this tip helpful. 🙂 I’m not sure how to add ISO 8601 numerical calendar weeks, but I can see how that would be useful!

  11. I set my regional settings to United Kingdom, has the same effect (running Lion). Best part: this also works on the iPhone (iOS5) and probably iPad. Beware that this also changes the way the date is shown (it says 5 january and not january 5 with UK settings)

    Also, the clock on top of my screen doesn’t say 19:00 PM but just 19:00 now, even though I did not have to delete the AM and PM in the other fields.

    I only had to change the currency back to Euro. I’m in the Netherlands but I prefer my computer to speak English to me 🙂

  12. Changing the mode isn’t much of a fix, I guess!
    Here is what I figured out:
    Just go into week view and and you can just pull the event to the desired time (;


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