What this converter does
This tool turns a 12-hour AM/PM time — the kind shown on most clocks, phones, and watches in the US — into its 24-hour equivalent, sometimes called military time. Pick the hour, the minute, and whether it's AM or PM, and the 24-hour reading appears immediately, alongside a four-digit military form and the number of minutes since midnight.
It exists for the two hours everyone second-guesses: 12:00 AM and 12:00 PM. Every other hour just shifts by 12 once you cross into the afternoon, but midnight and noon are where people write down the wrong number by hand.
How to use it
Three quick selections — the result updates as soon as any one of them changes.
- Choose the hour.Pick the hour exactly as it reads on a 12-hour clock, from 1 to 12.
- Enter the minutes.Type the minutes past that hour, from 00 to 59.
- Select AM or PM.Morning is AM; afternoon and evening are PM.
- Read and reuse the result.Copy it, print it, or download it as a CSV row.
How the conversion works
The rule has two branches, and the only exceptions are the hour 12 itself:
- AM: the 24-hour hour is the same number, except 12 AM becomes 00.
- PM: add 12 to the hour, except 12 PM stays 12.
1424-hour time = 14:30
Military digits = 1430
Minutes since midnight = 14 × 60 + 30 = 870
Midnight and noon
These are the two hours that break the simple pattern. 12:00 AM (midnight) is the very start of the day, so it becomes 00:00 — not 12:00. 12:00 PM (noon) is the midpoint of the day and keeps its number, becoming 12:00. Mixing these two up is the single most common 12-hour-to-24-hour mistake.
Going the other direction
Already have a 24-hour time and need the AM/PM version instead? The 24 to 12 hour converter on the homepage does the reverse conversion, and the 24-hour clock chart lays out every hour of the day both ways at a glance.
Quick examples
Common AM/PM times and their 24-hour equivalents.
| 12-hour | 24-hour | Military digits | Minutes since midnight |
|---|---|---|---|
| 12:00 AM | 00:00 | 0000 | 0 |
| 6:15 AM | 06:15 | 0615 | 375 |
| 12:00 PM | 12:00 | 1200 | 720 |
| 2:45 PM | 14:45 | 1445 | 885 |
| 9:30 PM | 21:30 | 2130 | 1290 |
| 11:59 PM | 23:59 | 2359 | 1439 |
Need to check a 24-hour value the other way round? The military time converter and the military time chart map every 24-hour hour back to its 12-hour reading.
Who uses it, and for what
- Travelers & expats reading a train, flight, or event schedule printed in 24-hour time.
- Military, medical, and emergency-services staff converting a civilian AM/PM time into the format used on the job.
- Developers double-checking a value before writing it into an ISO 8601 timestamp or a 24-hour form field.
- Anyone filling out a form that asks for 24-hour time but only knows the AM/PM version off the top of their head.
Working out the gap between two 24-hour times instead of converting a single one? The hours calculator handles that, breaks included.
Frequently asked questions
How do I convert 12-hour time to 24-hour time?
If the time is AM, the 24-hour hour is the same number, except 12 AM becomes 00. If the time is PM, add 12 to the hour, except 12 PM stays 12. For example, 3:15 PM becomes 15:15, and 12:30 AM becomes 00:30.
What does 12:00 AM become in 24-hour time?
12:00 AM, midnight, becomes 00:00 in 24-hour time. It's the one AM hour where the number changes, since there's no "12" at the very start of the 24-hour clock.
What does 12:00 PM become in 24-hour time?
12:00 PM, noon, stays 12:00 in 24-hour time. Noon is the midpoint of the day, so it keeps the number 12 in both formats.
Is 24-hour time the same as military time?
The digits are identical, so 14:30 and 1430 hours describe the same moment. Military usage typically drops the colon and reads the digits individually, such as "fourteen thirty," but the underlying numbering is the same.
Why do some countries use 24-hour time by default?
Most of Europe, Latin America, and Asia use the 24-hour clock for schedules, transport, and official documents because it removes AM/PM ambiguity entirely — every hour of the day has one unique number.
Is this converter free and private?
Yes. It's completely free with no sign-up, and the conversion runs entirely in your browser — nothing you type is uploaded or stored on a server.
Accuracy & sources
The conversion is standard time arithmetic: AM hours map directly except for the 12 AM → 00 exception, and PM hours add 12 except for the 12 PM exception, exactly as shown in how the conversion works. There is no rounding or approximation involved, and every worked example on this page has been independently verified by hand.
The 24-hour result follows the clock notation defined by ISO 8601, the international standard for representing dates and times, which specifies the 24-hour numbering used worldwide for schedules and timestamps. Written and reviewed by Fletcher Langley, and re-checked whenever the tool changes — last reviewed August 2026.
About the author
Operations and workforce-systems specialist with 14+ years inside shift-based industries and payroll platforms, and a BS in Industrial Engineering. Fletcher writes and reviews the calculators, converters, and guides here — from overnight-shift math to decimal payroll hours — drawing on years spent translating between 12-hour, 24-hour, and military time for real timesheets.
Written & reviewed by Fletcher Langley · Last updated: August 2026