Convert from 24 Hour to 12 Hour Time
Ever been stumped when you see a clock read something like 14:24? That's because the clock is using 24-hour time. This form of timekeeping is commonly used in Europe and other parts of the world outside of North America. So, how do you convert from a 24-hour clock to 12-hour time? Just follow these steps to find out.
Steps
Time Conversion Cheat Sheet
Doc:Time Conversion Chart
Converting Manually
- Learn how to convert the first twelve hours of 24-hour time to 12-hour time. In 24-hour time, 00:00 is equal to 12:00 AM, and then you can think of the rest of the hours between 00:00 and 12:00 as being equal to the hours between 12:00 AM and 12:00 PM on the 12-hour clock. This means that the conversions are as follows:
- 00:00 = 12:00 AM
- 01:00 = 1:00 AM
- 02:00 = 2:00 AM
- 03:00 = 3:00 AM
- 04:00 = 4:00 AM
- 05:00 = 5:00 AM
- 06:00 = 6:00 AM
- 07:00 = 7:00 AM
- 08:00 = 8:00 AM
- 09:00 = 9:00 AM
- 10:00 = 10:00 AM
- 11:00 = 11:00 AM
- Learn how to convert the second twelve hours of 24-hour time to 12-hour time. If there is a time that reads 12:00 or greater for the hour, know that it will convert to a PM-based time on the 12-hour clock. When the hour is greater than 12, subtract 12 from the hours and that will get you the time in PM. Here's how you do it:
- 13:00 - 12:00 = 1:00 PM
- 14:00 - 12:00 = 2:00 PM
- 15:00 - 12:00 = 3:00 PM
- 16:00 - 12:00 = 4:00 PM
- 17:00 - 12:00 = 5:00 PM
- 18:00 - 12:00 = 6:00 PM
- 19:00 - 12:00 = 7:00 PM
- 20:00 - 12:00 = 8:00 PM
- 21:00 - 12:00 = 9:00 PM
- 22:00 - 12:00 = 10:00 PM
- 23:00 - 12:00 = 11:00 PM
- Convert backwards from the 24-hour clock to the 12-hour clock. Once you know what to do whether you're working with a time between 00:00-12:00 (just add "AM" at the end) or a time between 12:00-00:00 (just subtract 12 and add "PM". at the end), then you're good to go when it comes time to convert from the 12-hour to the 24-hour clock. Here's how you do it:
- For times between 00:00 and 12:00 (12:00 AM - 12:00 PM.), just write down the time without using "AM" or "PM" So, 1:00 AM = 01:00, 2:00 AM = 02:00, 11:00 AM = 11:00, and so on.
- For times between noon and midnight (12:00 PM - 12:00 AM), just add 12. For example, 1:00 PM = 01:00 + 12:00, or 13:00, 2:00 PM = 02:00 + 12:00, or 14:00, 11:00 PM = 11:00 + 12:00, or 23:00, and so on.
- If the time is exactly 12:00 PM, then just write 12:00. If it's 12:12 PM, then just write 12:12
- There is no such thing as 24:00. 24:00 is really 00:00, and it means midnight.
- Just convert the minutes along with the hours. So, 22:34 in the 24-hour clock just becomes 22:34-12:00, or 10:34 PM.
Tips
- Depending on the display, a leading zero may be appended to a single digit hour.
- When you get up to 23:00, you start again at 00:00.
- The colon is not "pronounced" (same as AM/PM). "16:35" would be pronounced "sixteen thirty-five" or "thirty-five minutes past sixteen".
- Depending on the speaker's preference, leading zeros may be "pronounced" (as "zero" or "oh"). However, for times in the "zero hour" or midnight (00:00), both zeros are usually not pronounced. Example: 8:00 AM = 08:00 = "eight" = "eight hundred" = "zero-eight hundred" = "oh-eight hundred" = "a hundred minutes past eight".
- Should the colon be omitted when writing out the time, it is better to follow the time with the word "hours" to avoid confusion between 24-hour time and military time (i.e. "1600 hours").
- Another quick, easy-to-use method is to subtract 2 from the second digit and 1 from the first digit for any value over 12 (Ex: 17:00 - 2 = 5:00 PM; 22:00 - 2 = 10:00 PM). Should you get a negative value you'll have to "compensate" for it by subtracting the difference from the what the overall result result would have been given a zero in place of the negative number (luckily this only happens in two cases, 20:00 or 8:00 PM and 21:00 or 9:00 PM).
- It may help to think of the stroke of midnight as 24:00—even though it doesn't exist—as well as being 00:00 to understand the "quirky" transition from 23:59 to 00:00 (similar to the "quirky" transition from 12:59 AM/PM to 1:00 PM/AM).
- Practice makes perfect! If you have a digital device or appliance, there may be a setting that allows you to switch the time display form 12-hour time to 24-hour time.
- Be aware that countries such as the United States of America and Canada don't use 24-hour time in everyday life. Because of this, it is known as "Military Time", while other countries call it 24-hour time. In military time, there is no colon and the word "hours" is placed, while 24-hour time uses a colon without using the word "hours".
