The following tool will accept an integer number that represents an Epoch time in seconds and convert it to three formats:

  1. It will convert the epoch to UTC
  2. Then to your local timezone
  3. Finally to ISO format

Operation instructions: Fill in the above box with a valid value and click on the ‘Epoch to Date’ button. The results will appear instantly below the button.

Valid values start from -8,640,000,000,000 to +8,640,000,000,000 (including). Value 0 will return 1970-01-01T00:00:00.000Z which is the reference point for the Unix Epoch.

Unix time (also known as POSIX time or Epoch time) is a system for describing instants in time, defined as the number of seconds that have elapsed since 00:00:00 Coordinated Universal Time (UTC), Thursday, 1 January 1970, not counting leap seconds. It is used widely in Unix-like and many other operating systems and file formats. Because it does not handle leap seconds, it is neither a linear representation of time nor a true representation of UTC. Unix time may be checked on most Unix systems by typing date +%s on the command line.

From Wikipedia