Is 12 AM midnight or noon?

Midnight, the start of the day, written 00:00. 12 PM is noon. The convention is genuinely confusing, which is why timetables often write the words instead.

Date & TimetimeUnited States only

Military Time Converter

Convert between 12-hour and 24-hour time. Midnight and noon are the cases that trip people: 12 AM is 00:00 and 12 PM is 12:00, which feels backwards.

Also called: 24 hour clock converter, am pm converter.

24-hour time

14:30

14:30 in 24-hour time is 2:30 PM in 12-hour time. Neither midnight nor noon, so the conversion is unambiguous.

12-hour time

2:30 PM

Minutes past midnight

870

Spoken form

14 30 hours

On midnight and noon

Neither midnight nor noon, so the conversion is unambiguous.

How this is calculated

Method and background

How this is calculated

Converting to 24-hour takes the hour modulo twelve and adds twelve for PM. The awkwardness is entirely at the two twelves: 12 AM is the start of the day at 00:00, and 12 PM is midday at 12:00, so the AM one is earlier despite the larger number. Many style guides recommend writing noon and midnight in words for exactly this reason.

twelve becomes zero before adding twelve for PM, which is why noon and midnight are the awkward cases

p: 1 for PM, 0 for AM

Worked examples

Each of these is asserted on every build. If a change to the engine ever moved one of these answers, the build would fail before the page could print it.

half past two in the afternoon

Hour: 14
Minute: 30
That hour is: 24-hour
If 12-hour, is it: PM

24-hour time14:30

arithmetic identity

Open this example

twelve AM is midnight

Hour: 12
Minute: 0
That hour is: 12-hour
If 12-hour, is it: AM

24-hour time00:00

boundary: the case everyone gets wrong

Open this example

twelve PM is noon

Hour: 12
Minute: 0
That hour is: 12-hour
If 12-hour, is it: PM

24-hour time12:00

boundary

Open this example

Method and limits

What it assumes

A 24-hour clock from 00:00 to 23:59.

What it deliberately does not model

24:00 as an end-of-day marker is valid in ISO 8601 but is not produced here.

Formula version 1.0.0 · definition 1.0.0 · United States · Report a problem with this calculator

Frequently asked questions

Is 12 AM midnight or noon?: Midnight, the start of the day, written 00:00. 12 PM is noon. The convention is genuinely confusing, which is why timetables often write the words instead.