What is a Unix Timestamp?

The Unix timestamp (also known as Epoch time) is a system for describing a point in time. It is the number of seconds that have elapsed since the Unix Epoch, minus leap seconds.

The Unix Epoch

The Epoch is January 1, 1970 at 00:00:00 UTC. Computers use this format because it is much easier to store and calculate dates as a single number (integer) rather than complex strings like "2025-12-31".

Seconds vs Milliseconds

Seconds (10 digits): Standard Unix timestamp used in PHP, Python, and MySQL.
Milliseconds (13 digits): Used in JavaScript (Date.now()) and Java. Our tool automatically detects which one you are using.