Unix

The Unix calendar is a method of storing the passage of time in one number, the number of seconds since midnight on January 1, 1970 UTC. This number is how all computers calculate time. To display the number as a human readable time, computers translate into the correct number of hours, minutes, and seconds in the specific timezone that the user is in. The universality of the calendar is why it is so useful in the modern world; it spans across all time zones, political boundaries, and geography with one single number. Every day the number grows by 86400 seconds. A date such as November 13, 2025, 15:00:00 would be stored as 1763064000.