How to Convert a Unix Timestamp to a Readable Date

Somewhere in a log file or a database, you find `1721390400` and need to know what time it represents. That is a Unix timestamp — the number of seconds since January 1, 1970 — and it is how computers store time almost everywhere. Converting it to a human date, and back again, is a constant task for developers. This guide explains what the timestamp is, the seconds-versus-milliseconds trap, and how time zones factor in.

What a Unix timestamp is

A Unix timestamp counts the seconds elapsed since the "epoch" — midnight UTC on January 1, 1970. It is a single integer with no time zone, no formatting, and no ambiguity, which is exactly why systems love it. `0` is the epoch itself; `1721390400` is a moment in July 2024. Humans cannot read it at a glance, hence the need to convert.

How to convert a timestamp with this tool

1. Open the Timestamp Converter tool.
2. Paste a Unix timestamp to get a readable date, or enter a date to get the timestamp.
3. Read the result in the format you need.

Everything runs in your browser — conversion is local and instant.

The seconds vs. milliseconds trap

This catches everyone at least once. Unix timestamps come in two flavors:

• Seconds — the classic form, 10 digits for current dates (e.g. `1721390400`).
• Milliseconds — used by JavaScript and many APIs, 13 digits (e.g. `1721390400000`).

Feed a milliseconds value into a seconds parser and you land thousands of years in the future; do the reverse and you land in 1970. If a converted date looks absurd, you almost certainly mixed up the units — check the digit count.

Time zones matter

The timestamp itself is always UTC, but you usually want to see the date in a specific time zone. The same instant is a different wall-clock time in London, New York, and Tokyo. When converting, be clear whether you are reading the result as UTC or your local time, especially when comparing timestamps from systems in different regions.

Common uses

• Read timestamps in logs to see when an event happened.
• Decode a JWT's `exp` claim to check token expiry — pair with JWT Decoder.
• Debug scheduling by converting stored times to readable dates.
• Set a specific time by finding its timestamp for a config or test.

Related tools

For calculating durations between human dates rather than converting timestamps, Age Calculator handles date arithmetic. Working with data files full of timestamps? CSV to JSON helps restructure them.

Privacy and limits

Conversion is fully local — no upload, nothing stored, offline once loaded. Open the Timestamp Converter tool to make sense of epoch time.