Unix Timestamp Converter

Convert Unix timestamps in seconds or milliseconds to UTC dates, and timezone-stamped ISO dates back.

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Timestamp to UTC date

Select the unit used by your Unix timestamp.

Timezone date to timestamp

Include Z or a UTC offset so the instant is unambiguous.

Example: 2026-09-25T08:30:00+08:00

How timestamp units work

Unix timestamps count time from 1970-01-01 UTC. Seconds and milliseconds differ by a factor of 1,000; choose the unit explicitly. Results include a UTC ISO date and both timestamp units.

Why must the date include a timezone?

A local clock time can refer to different instants in different timezones. Enter an ISO 8601 date and time ending in Z or an explicit offset such as +08:00. This tool does not guess your device timezone or handle leap seconds.

Convert a log timestamp to a UTC date

Paste the integer timestamp, select seconds or milliseconds, then convert. To go the other way, enter an ISO date and time with Z or an explicit offset such as +08:00.

Example and expected result

1700000000 seconds is 2023-11-14T22:13:20.000Z. The ISO value 2023-11-15T06:13:20+08:00 converts back to 1700000000 seconds and 1700000000000 milliseconds. A local date without a timezone is rejected rather than guessed.