Unix timestamp converter
Convert a Unix timestamp to a readable date and back, in seconds or milliseconds.
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About this tool
Turn a Unix timestamp into a date you can read — in UTC, in your own time zone and as ISO 8601 — or go the other way and get the timestamp for a date and time you choose. The unit is always explicit: you say whether the number is seconds or milliseconds rather than letting the tool guess from its length, and if it looks like the other unit you get a warning instead of a date that is quietly fifty years out. Everything is computed in your browser while you type.
Using this tool
Seconds or milliseconds — how do I tell?
By where the number came from, not by its length. JavaScript’s Date.now and most Java APIs give milliseconds, so thirteen digits; Unix tools, PostgreSQL, MySQL and most JSON APIs give seconds, so ten. The tool warns when the digit count disagrees with the unit you picked.
Why is my date one day out?
Almost always a time zone. A timestamp is an instant, not a date, so the same moment is 31 December in New York and 1 January in London. Both readings are shown side by side for exactly this reason.
What is the 2038 problem?
Systems that store Unix time in a signed 32-bit integer run out at 03:14:07 UTC on 19 January 2038. This tool uses JavaScript numbers, so it handles dates far beyond that — but the system that produced your timestamp may not.
Does it account for leap seconds?
No, because Unix time does not. It counts every day as exactly 86,400 seconds, which is why it can be converted to a date with arithmetic alone.
Tool activity
Simple tools for everyday work.
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