Unix Timestamp FAQ

A Unix timestamp, also called epoch time or POSIX time, counts elapsed seconds since 00:00:00 UTC on January 1, 1970. Some systems store the same value in milliseconds instead of seconds.

Both formats are common. Current epoch seconds usually contain 10 digits, while epoch milliseconds usually contain 13 digits. This converter can switch units manually and detects seconds or milliseconds when you paste a timestamp.

Paste or enter the timestamp, choose seconds or milliseconds, and select a timezone. The corresponding local date, time, timezone abbreviation and ISO 8601 value appear immediately.

Enter a date and time, select the timezone in which that wall-clock time occurs, then copy the generated epoch value in seconds or milliseconds.

The timestamp itself represents one absolute instant and has no timezone. Timezones and daylight saving rules matter only when that instant is displayed as a local date, or when a local date is converted back to an epoch value.

Yes. Choose UTC, a conventional fixed GMT offset such as GMT+2, or an IANA timezone such as Europe/Sofia, America/New_York or Asia/Tokyo. Named zones apply historical and daylight saving rules.

Yes. Negative Unix timestamps represent dates before the Unix epoch, and fractional seconds are supported when converting a timestamp to a date.

Some older systems store epoch seconds in a signed 32-bit integer, which overflows on January 19, 2038. Modern 64-bit timestamp storage supports a much wider date range.

No. Conversions run locally in your browser. Only the selected timezone and theme preference are saved in local storage on your device.