Date & Time

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12 Hour to 24 Hour Time Converter.

Convert between 12-hour AM/PM time and 24-hour military time in either direction, with midnight and noon handled correctly.

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12-hour → 24-hour
24-hour time: 00:00

24-hour time

00:00

Breakdown

Input12:00 AM

How to Use

The two cases people get wrong: 12:00 AM is midnight (00:00), not 12:00, and 12:00 PM is noon (12:00). For every other hour, PM adds 12 and AM stays the same.

FAQs

Is 12:00 AM midnight or noon?

12:00 AM is midnight, which is 00:00 in 24-hour time. 12:00 PM is noon, which is 12:00. This is the single most common mistake in time conversion, and this converter handles both explicitly.

How do I convert PM time to 24-hour time?

For any hour from 1 PM to 11 PM, add 12: 3:00 PM becomes 15:00 and 11:59 PM becomes 23:59. The exception is 12 PM, which stays 12:00.

How do I convert AM time to 24-hour time?

Hours from 1 AM to 11 AM are unchanged, just zero-padded: 7:05 AM becomes 07:05. The exception is 12 AM, which becomes 00:00.

What is military time?

Military time is the 24-hour clock written without a colon, such as 1345 for 1:45 PM. Hours run from 0000 (midnight) to 2359, so no AM/PM marker is needed and there is no ambiguity.

Can I convert in the other direction?

Yes. Use the swap control to switch to 24-hour to 12-hour mode, then enter a time like 00:30 to get 12:30 AM or 13:45 to get 1:45 PM.

Cite this calculator

Canonical URL: https://mathify.one/zh/date/time-format

Cite as: Mathify. (2026). 12小时制转24小时制转换器. https://mathify.one/zh/date/time-format

Use Cases

Scheduling Across Time Formats

Quickly convert times for travel, work shifts, or international meetings to avoid confusion between AM/PM and military time.

Example: Convert 3:45 PM to 15:45 for a flight itinerary.

Understanding Military Time

Learn how to read and write military time by converting familiar AM/PM times to 24-hour format.

Example: See that 8:30 AM becomes 08:30.

Frequently Asked Questions

How do I convert 12 AM to 24-hour time?
12 AM (midnight) is 00:00 in 24-hour time. The converter automatically adjusts the hour to 0 when you select AM and hour 12.
What is 12 PM in 24-hour time?
12 PM (noon) is 12:00 in 24-hour time. The converter keeps the hour as 12 when you select PM and hour 12.
Can I convert from 24-hour time back to AM/PM?
Yes, the converter has a one-click swap feature. Enter a time in 24-hour format (HH:MM) and click swap to see the equivalent AM/PM time.

Tips & Common Mistakes

Tips

  • Remember: 12 AM is 00:00, and 12 PM is 12:00. The converter handles these correctly.
  • For times from 1:00 AM to 12:59 PM, the hour stays the same in 24-hour format (e.g., 9:30 AM = 09:30).
  • For times from 1:00 PM to 11:59 PM, add 12 to the hour (e.g., 3:00 PM = 15:00).
  • Use the swap button to quickly toggle between formats and double-check your conversions.

Common Mistakes to Avoid

  • Assuming 12 AM is 12:00 in 24-hour time. It's actually 00:00.
  • Forgetting to add 12 to PM hours after 12 PM. For example, 1 PM is 13:00, not 01:00.
  • Entering minutes outside the 0-59 range. The converter expects valid minute values.

Last updated: August 13, 2026