Unix Timestamp Converter

Convert Unix timestamps to human-readable dates and back. Handles seconds and milliseconds, UTC and local time.

All processing happens in your browser. Nothing is uploaded.

Enter a timestamp

How to use

  1. Enter a Unix timestamp. The field is prefilled with the current time.
  2. The UTC and local equivalents update as you type.
  3. Click Now to reset to the current timestamp.

About Unix timestamps

A Unix timestamp counts the seconds elapsed since 1 January 1970 at 00:00:00 UTC, a moment known as the epoch. Because it is a single integer with no timezone attached, it is unambiguous — which is exactly why it became the default way to move times between systems.

The seconds-versus-milliseconds split causes more bugs than anything else here. Unix tooling and most databases use seconds; JavaScript’s Date.now() and the JVM use milliseconds. Mixing them silently yields dates roughly a thousand times too far from now, which is usually obvious, but a value off by a factor of 1000 in the other direction lands in 1970 and is easy to misread as “no value set”.

Timestamps carry no timezone. The local time shown above is your browser’s interpretation; the same timestamp renders differently for a user in another region. Store and transmit timestamps in UTC, and convert only at the point of display.

Frequently asked questions

Seconds or milliseconds — how does it decide?

Values with 13 or more digits are read as milliseconds, shorter ones as seconds. This heuristic covers essentially every timestamp you will encounter between 1970 and the year 2286.

Why does the local time differ from what I expect?

Local time uses your device's timezone and daylight-saving rules. If you need a stable reference, use the UTC value.

Can I convert dates from before 1970?

Yes. Negative timestamps represent times before the Unix epoch and are handled correctly.

What is the year 2038 problem?

Systems storing timestamps in a signed 32-bit integer overflow on 19 January 2038. This tool uses JavaScript numbers, so it is unaffected, but the systems producing your timestamps may not be.