Timestamp Converter
Convert Unix timestamps to and from ISO dates, local time, and UTC. Free online tool with millisecond support. No signup needed.
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Frequently asked questions
- What is a Unix timestamp?
- The number of seconds (or milliseconds) since January 1, 1970 UTC (the Unix epoch). A universal, timezone-neutral way to represent a moment in time.
- Seconds or milliseconds?
- JavaScript and JSON typically use milliseconds. Linux, databases, and most APIs use seconds. Use the dropdown to switch.
- How does it handle time zones?
- Local time shows the timestamp in your browser's time zone. UTC and ISO 8601 are both in UTC. The relative time is calculated from now.
- What happens to timestamps after year 2038?
- 32-bit Unix timestamps overflow in January 2038 (Y2K38 bug). JavaScript uses 64-bit numbers internally, so this tool works well beyond that date.
- What does the relative time line show?
- The distance from now in the largest sensible unit, so a value a few hours ahead reads as in 3 hours and one from last year reads as 1 year ago, phrased in the page language.
- Why does my timestamp show nothing?
- Only positive numbers are treated as valid, so 0, a negative value for a pre-1970 date, or text with stray characters produces no output. Check that the unit selector matches your value, since a seconds value read as milliseconds lands in January 1970.