Unix Timestamp to Date Converter (Epoch Time)

Converts a Unix timestamp — seconds since 1 January 1970 UTC — into a date, or builds a timestamp from a date. The offset sets the local zone the date is read in, such as 9 for Japan.

This tool converts between Unix time and a date. Unix time counts the seconds elapsed since midnight UTC on 1 January 1970, and is also called epoch time or a Unix timestamp.

u = 86400 n + 3600 h + 60 m + s - 3600 z

Here $n$ is the day number of the date, $h$ , $m$ and $s$ the hours, minutes and seconds, $z$ the UTC offset and $u$ the timestamp. The date is turned into seconds and the local offset is removed to bring it back to UTC.

Why time is kept in seconds

As a single integer, a moment can be recorded without carrying a calendar or a time zone along with it, and comparisons and differences are ordinary arithmetic. That is why logs and databases hold time in this form.

Worked example

The timestamp 1767225600 corresponds to 09:00:00 on Thursday 1 January 2026 in a zone at UTC+9.

Dividing 1767225600 by 86400 gives exactly 20454, so in UTC the moment is midnight on 1 January 2026. Adding the nine-hour offset, 32400 seconds, brings it to 09:00 locally.

The year 2038 problem

Held as a signed 32-bit integer, Unix time overflows into negative numbers on 19 January 2038. Modern systems use 64 bits and are unaffected, but the limit survives in older hardware and in some file formats.

Points to watch

Leap seconds are not counted. Unix time is defined with every day exactly 86400 seconds long, so this is the specified behaviour rather than an approximation.