Date & time

Unix timestamp converter

Convert seconds or milliseconds to an exact UTC ISO date and back.

Processed locally

Choose units explicitly. ISO input requires a four-digit year and trailing Z. Seconds allow at most three fractional digits.

Your answer will appear here.

Help and method

Use YYYY-MM-DDTHH:mm:ss[.sss]Z. UTC conversion validates calendar dates; local zones and UTC offsets are not accepted. No unit is inferred from the number of digits.

Methods and reliability

Worked example

An example you can try or adapt to your own values.

Direction
Unix to ISO
Unit
Seconds
Input
0

Result

1970-01-01T00:00:00.000Z