Unix Timestamp Converter
Convert Unix timestamps to readable dates and times for development, logs, APIs and debugging.
Unix Timestamp Converter online
Convert a Unix timestamp to a human-readable date, or turn a date and time into a timestamp — the two directions developers need when reading logs, debugging APIs and checking expiry times.
How it works
Unix time counts the seconds since 1970-01-01 00:00:00 UTC — the epoch — ignoring leap seconds. This tool accepts both seconds and milliseconds: a value with up to 10 digits is read as seconds, a longer one as milliseconds, which bridges the two conventions you meet in practice — most server logs and APIs use seconds, while JavaScript's Date works in milliseconds. Converting a timestamp shows three renderings of the same instant: your browser's local time string, the ISO 8601 UTC string, and a locale-formatted version, so time-zone differences are visible at a glance. The reverse direction takes a date and time you pick and returns its timestamp in seconds.
Worked example
The timestamp 1700000000 is Tuesday, 14 November 2023, 22:13:20 UTC. The same instant written in milliseconds is 1700000000000 (13 digits) — pasting either form gives the same date. Since a day is exactly 86,400 Unix seconds, adding that to the timestamp gives 1700086400, the same time on 15 November.
How to use this tool
- To convert a timestamp, paste it into the number field and run — seconds or milliseconds both work.
- To convert a date, pick it in the date-and-time field and run to get the timestamp in seconds.
- Compare the local-time and UTC lines side by side when debugging a time-zone bug.
Common uses
Reading server logs and API responses, checking when a token or session expires (the iat and exp claims inside a JWT are Unix seconds), verifying cron schedules and database records, and converting the created_at fields you meet while debugging.
Privacy and browser processing
The conversion runs locally in your browser — the timestamps and dates you enter are never uploaded.
Frequently asked questions
Why does my timestamp show a date in 1970, or tens of thousands of years in the future?
A seconds/milliseconds mix-up. Read a seconds value as milliseconds and you land in January 1970; read a millisecond value as seconds and you land millennia ahead. This tool guesses from the digit count — 10 digits or fewer means seconds — which covers most values you will paste.
What is the year 2038 problem?
Systems that store Unix time in a signed 32-bit integer overflow at 2,147,483,647 seconds — 19 January 2038, 03:14:07 UTC — and wrap around to negative values, i.e. dates in 1901. Modern 64-bit systems are unaffected, but embedded devices and old file formats still carry the limit.
Does Unix time include leap seconds?
No. Unix time assumes every day is exactly 86,400 seconds and ignores the leap seconds occasionally added to UTC. The two clocks therefore drift apart by a second at each leap second — irrelevant for nearly all software work.
Which time zone does the result use?
All of them at once: the first line renders in your browser's local time zone, the ISO line is UTC, and the third line is a locale-formatted version. For the reverse conversion, the date and time you pick is interpreted in your local time zone.