How epoch converter works
Unix time (also called epoch time or POSIX time) counts the seconds elapsed since 00:00:00 UTC on 1 January 1970, ignoring leap seconds. It is how most operating systems, databases and APIs store points in time, which is why logs and JSON payloads are full of values like 1700000000. Thirteen-digit values are the same moment expressed in milliseconds instead of seconds.
This converter works in both directions. Paste a timestamp and it returns the ISO 8601 UTC date and time, the separate date and time parts, and the weekday; type a date such as 2009-02-13 23:31:30 and it returns the matching timestamp in seconds or milliseconds. All conversions are done against UTC so the results are unambiguous: 2009-02-13 23:31:30 UTC is always epoch 1234567890, no matter where in the world you are.
The tool accepts negative timestamps for dates before 1970 and rejects values beyond the range JavaScript dates can represent (about ±273,790 years). It validates impossible calendar dates like 30 February and rounds leap years correctly. The page also shows the converted moment in your browser's local time zone for reference, and everything runs entirely in your browser — no timestamps are uploaded.