Unix Timestamp Converter
Runs entirely in your browser — nothing you type is sent anywhere.
What this tool does
Converts Unix timestamps (seconds or milliseconds since 1970) to ISO 8601 dates and back — always in UTC, with the epoch value shown in both units plus the weekday. Handles negative timestamps (before 1970), millisecond precision and explicit offsets like +02:00.
Why it refuses what other converters guess
A time without a timezone, like 2026-07-14T12:00, reads differently on every computer that opens it — most converters silently use your local zone and call it a day, which is how meetings end up an hour off. This tool refuses the ambiguity and tells you to add Z or an offset. Impossible dates refuse too: February 30th is an error here, not silently March 2nd. Exactness over convenience — and, as with every tool here, the page is static and keeps working offline, verified by our automated tests on every release.