I noticed that Virgin America uses a 12-hour time format, while Qatar Airways always uses a 24-hour time format.

Virgin America:

Virgin America

Qatar Airways:

Qatar Airways

1:00AM = 0100H
9:00PM = 2100H
12am = 0000H
12pm = 1200H

Is it okay to use 12MN or 12NN if I choose the 12-hour clock time?

Which time format would be more convenient and understandable for flight bookings?

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    localization is really important to show time-zones and time...You should have it according to user preferences.
    – Abektes
    Commented May 24, 2017 at 9:46
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    But what about the user that is not logged in? Commented May 24, 2017 at 10:10
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    12pm is not 2400H, btw.
    – Kevin
    Commented May 24, 2017 at 16:44
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    @DimitraMiha Cookies can store personalization data, and you can generally get a best guess as to someone's location by using their IP. This doesn't necessarily work for​ someone behind a VPN or proxy, but generally people behind those will be used to odd localization.
    – anon
    Commented May 24, 2017 at 18:16
  • @Kevin I submitted an edit to fix that. Commented May 24, 2017 at 20:29

3 Answers 3


Times for flights are almost always given as local time in a 24-hour format.


Most airlines use the 24-hour clock system when telling time. They use this system when assigning trip departures, check-in times and other forms of time designation. The 24-hour clock alleviates communication problems and is more convenient.


I think it is interesting to read the following article on times and how people might miss the flight because of time format


This is a very interesting case for further research, but I would suggest going for 24-hour clock.

What I see is that this is a convention. Since most companies use the 24-hour clock, it is better to use the same way, in order to avoid confusion for your passengers.


Make your decision based on your user's location. So, someone in the USA will see AM/PM times and someone in Qatar will see 24H.

Having just one of the two will confuse users of the other region.


More information here: Date and time representation by country

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    More information, here en.wikipedia.org/wiki/Date_and_time_representation_by_country Commented May 24, 2017 at 10:12
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    What can you say, example about a user from US (with AM/PM) book a flight going to Qatar, one way. And as going back to US, he/she use the same site in QATAR (with 24H time). There is some inconsistency which become more confusing to the users.
    – Sknny
    Commented May 24, 2017 at 14:17
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    As someone who sometimes uses a website when on vacation: No! Not based on location. Setting the default based on location may be fine, but allow users to set it to a sane setting.
    – Hennes
    Commented May 24, 2017 at 17:26
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    I don't think this is correct. What if I'm an user who uses 24 hours time and access the site from my hotel in US? Will I get something confusing just because I accessed it from another country?
    – Devin
    Commented May 24, 2017 at 17:39
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    Default should be 24H, even US citizens get confused. If you add both options, that's great, but I think 24H should be default. No ambiguity there, and no possible confusion. Commented May 24, 2017 at 20:17

People who are used to the am/pm format will be able to correctly understand the 24:00 format. People who are used to the 24:00 format will occasionally misunderstand 12:00 pm. Even people who are used to am/pm will occasionally misunderstand 12:00 pm.

So if context doesn't clarify if we're talking midnight or noon, and it's important to avoid misunderstandings, use 24:00. Same if you expect a lot of international users. International long distance flights satisfy all of these these criteria. US inland flights don't.

  • For international long distance flights, use 24:00.

  • For US domestic flights, both options are viable.

  • If your site displays both intercontinental and domestic US flights, use 24:00 to maintain consistency.

  • Ideally you provide an option that allows the user to easily show the second format.
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    Ironically, the list of people who misunderstand 12:00pm includes the OP... :-) Commented May 24, 2017 at 17:50
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    Note that 24:00 on May 1 is the same as 0:00 on May 2, though I would suggest such a time should only be used to describe something that begins earlier on the same day and ends at midnight (e.g. describing something as running from 18:00-24:00 on May 1 makes it visually clear that the interval in question is six hours).
    – supercat
    Commented May 24, 2017 at 17:57
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    It is not true that people who are used to the am/pm format will correctly understand the 24:00 format. To a person used to the am/pm format, a time like 07:00 is ambiguous and may be misunderstood.
    – ajd
    Commented May 24, 2017 at 21:36
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    @AlexanderDunlap, someone used to AM/PM seeing "07:00" will be prompted to ask "Is that AM or PM?". Someone used to 24-hour time seeing "7:00 PM" will initially think "07:00". Which situation do you think has less potential for mistakes?
    – Mark
    Commented May 25, 2017 at 0:18
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    @FabioTurati According to this I think you cannot say "misunderstand".
    – Axel
    Commented May 25, 2017 at 9:25

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