Unix Timestamp Converter

A Unix timestamp is the number of seconds (or milliseconds) elapsed since January 1, 1970 00:00:00 UTC — called the Unix Epoch. It is the universal standard for representing time in programming, databases, and APIs.

This date was chosen by the Unix developers at Bell Labs in the early 1970s as a convenient round number close to when the Unix system was being created. It is arbitrary but has become universal.

32-bit systems store Unix timestamps as signed integers, which overflow on January 19, 2038 at 03:14:07 UTC. 64-bit systems don't have this problem — they can represent dates billions of years into the future.

Unix timestamps in seconds are 10 digits long (~1,700,000,000). Millisecond timestamps are 13 digits (seconds × 1000). Many JavaScript APIs (Date.now()) use milliseconds; most databases and server-side APIs use seconds.