About Timestamp Converter
Paste an epoch number or a date in almost any format and see it every other way at once - seconds, milliseconds, ISO 8601, HTTP date, and the wall-clock time in whichever zone you pick.
Seconds or milliseconds
Unix time is defined in seconds, but JavaScript, Java and most log formats use milliseconds, and the two are indistinguishable without context. Digit count decides it here: a ten-digit number is read as seconds, a thirteen-digit one as milliseconds. Reading a millisecond value as seconds is the classic version of this mistake - it lands you in the year 45000.
Offsets are not fixed
A time zone is not a constant offset. New York is five hours behind UTC in January and four in July, so converting a timestamp needs the zone plus the instant, not just a number. The offset shown is the one that zone was actually on at that moment.
Frequently asked questions
- What exactly is the Unix epoch?
- Midnight UTC on 1 January 1970. A Unix timestamp counts the seconds elapsed since then, and negative values point at dates before it.
- Does Unix time account for leap seconds?
- No. It assumes every day is exactly 86,400 seconds, so a leap second repeats a value rather than adding one. That is deliberate and makes arithmetic on timestamps simple.
- Why does my date show a day earlier or later than expected?
- Almost always a time zone difference. A timestamp is a single instant, but that instant falls on different calendar days around the world - which is why storing dates as UTC and converting only for display avoids so much pain.