Unix Timestamp Converter
Turn an epoch number into a date, or a date into a number.
About this converter
Paste either a Unix timestamp or a date, and get every other form of it back: seconds, milliseconds, ISO 8601, UTC, your local time with the offset spelled out, and how long ago it was.
You do not have to say which you have — a run of digits is a timestamp and anything else is a date. Putting a number in the date box is the entire failure mode of every converter that makes you choose first.
Seconds and milliseconds are told apart by size, which sounds fragile and is not: a ten-digit number is seconds and a thirteen-digit one is milliseconds, and the boundary between them sits tens of thousands of years away from any date anyone actually converts. Microsecond timestamps, which turn up in some database exports, are handled too.
The local line shows your machine's time zone by name and its current offset, because "is this UTC or is it mine" is the question that costs the most time when reading a log.
Frequently asked questions
What is a Unix timestamp?
The number of seconds since midnight UTC on 1 January 1970. It is a single number with no time zone attached, which is precisely why systems use it — there is no ambiguity about what moment it refers to. The ambiguity arrives when something displays it.
How does it know seconds from milliseconds?
By size. A current timestamp in seconds is ten digits; in milliseconds it is thirteen. For the boundary to be wrong you would need a date in the year 5138 or before 1973, which is not what anyone is pasting in. Sixteen-digit microsecond values are recognised too.
Why does the local time differ from what I expected?
The local line uses your computer's time zone, shown by name with its offset. If that is wrong, your machine's clock or zone setting is wrong — the UTC and ISO lines are unaffected, since those carry no zone at all.
What is the 2038 problem?
Systems storing the timestamp in a signed 32-bit integer run out of room on 19 January 2038 and wrap round to 1901. Anything using 64-bit time — which is most current software — is unaffected for about 292 billion years. It still matters for old embedded systems and some database columns.
Does what I paste get sent anywhere?
No. The conversion runs in your browser, on your own machine — that is why the result appears as you type rather than after a wait. Nothing is uploaded, nothing is logged, and closing the tab is the end of it. This matters more here than on most pages: tokens, keys and internal data get pasted into tools like this constantly, and most of them are a form that posts to a server.