Staaarter

Convert 24hr Clock to 12hr

Parses one or more 24-hour clock times, written as HH:MM or HH:MM:SS, one per line, and converts each into standard 12-hour AM/PM format, handling the midnight and noon edge cases correctly. A free online tool from Staaarter, right in your browser.

Runs locallyUpdated 2026-08-05
By Staaarter Team
clock-formatconversion

Overview

Introduction

24-hour "military" time is unambiguous and common in logs, APIs, and many countries, but everyday reading and writing often calls for the familiar 12-hour AM/PM format instead.

This tool converts between the two instantly, correctly handling the midnight and noon edge cases that trip up manual conversion.

What Is Convert 24hr Clock to 12hr?

A 24-hour-to-12-hour clock format converter that accepts HH:MM or HH:MM:SS and returns the equivalent 12-hour AM/PM string.

It is a pure text-format converter, it does not touch timezones or calendar dates, only the way a single clock time is displayed.

How Convert 24hr Clock to 12hr Works

Each line is validated as a 24-hour time with hours from 00 to 23, then the hour is reduced modulo 12, with a 0 result mapped to 12.

The AM/PM label is chosen based on whether the original 24-hour value was below 12 (AM) or 12 and above (PM).

When To Use Convert 24hr Clock to 12hr

Use it when you have a 24-hour timestamp from a system log, API, or spreadsheet and need to present it in familiar AM/PM format for readers.

For the reverse direction, use Convert 12hr Clock to 24hr instead.

Features

Advantages

  • Correctly handles the midnight and noon edge cases, a common source of manual conversion errors.
  • Converts multiple times at once, one per line.
  • Preserves an optional seconds field if present in the input.

Limitations

  • Only accepts strict HH:MM or HH:MM:SS clock times, it does not parse full date-time strings.
  • Does not perform any timezone conversion, the output is the same instant in the same timezone as the input.

Examples

Converting an afternoon time

Input

14:30

Output

2:30 PM

14:30 in 24-hour time is 2:30 PM in 12-hour time.

Converting midnight

Input

00:00

Output

12:00 AM

Midnight is written as 00:00 in 24-hour time but 12:00 AM in 12-hour time.

Best Practices & Notes

Best Practices

  • Double-check midnight and noon conversions manually the first few times, since they're the most common source of off-by-twelve errors.
  • Include the seconds field in the input whenever precision to the second matters, it carries through to the output unchanged.

Developer Notes

The parser uses `/^([01]?\d|2[0-3]):([0-5]\d)(?::([0-5]\d))?$/`, then computes `hours24 % 12` for the 12-hour value, remapping a result of 0 to 12, and picks AM for `hours24 < 12` and PM otherwise, all as plain string and number logic with no Date object involved.

Convert 24hr Clock to 12hr Use Cases

  • Displaying a 24-hour system timestamp in a friendlier AM/PM format for end users
  • Converting a schedule or timetable exported in military time for a general audience
  • Preparing readable meeting or event times from 24-hour source data

Common Mistakes

  • Assuming 00:00 converts to "0:00 AM" instead of the correct "12:00 AM".
  • Passing a full date-time string instead of a bare clock time, which fails the strict HH:MM(:SS) validation.

Tips

  • Paste an entire list of 24-hour times at once, each line converts independently.
  • Use Convert 12hr Clock to 24hr to reverse the conversion and verify a result.

References

Frequently Asked Questions