Unix Timestamp Converter
Convert between Unix timestamps (seconds or milliseconds) and ISO 8601 dates in both directions.
A Unix timestamp counts the number of seconds elapsed since the epoch—January 1, 1970 at 00:00 UTC. It is the standard way to store time in logs, databases, and APIs because it is unambiguous and independent of time zone.
Some systems use milliseconds instead of seconds, giving a 13-digit number instead of 10. Both fields stay synchronized so you can tell which one you are looking at without mental arithmetic.
Ten digits means seconds, thirteen digits means milliseconds. Both fields update together so you never have to guess which unit you are looking at.
Common uses
- Decoding an exp claim from a JWT or an API error into a human-readable date.
- Building a query against a log system that expects epoch milliseconds.
Frequently asked questions
- Is the timestamp in seconds or milliseconds?
- A 10-digit number is seconds (current epoch); a 13-digit number is milliseconds. This tool converts both at once.
- Why is 1970 the start?
- January 1, 1970 was chosen as the Unix epoch by the designers of the operating system in the late 1960s and has since been adopted widely as a portable reference point.
- Will timestamps run out in 2038?
- The old 32-bit signed integer limit causes a rollover on January 19, 2038. Modern systems use 64-bit integers, which have no practical limit for thousands of years.
- What is the current timestamp?
- The tool shows both seconds and milliseconds for any date you enter. For 'now', use Date.now() in your browser console.