Unix Timestamp Explained

Seconds from the epoch

A Unix timestamp is the number of seconds since 1 January 1970 UTC, not counting leap seconds in most programming libraries. It is timezone-agnostic until you format it for display.

Seconds or milliseconds

JavaScript Date.now() is milliseconds. Many APIs use seconds. A 13-digit integer is usually milliseconds. A 10-digit integer is usually seconds. The timestamp converter applies that rule.

JWT and logs

JWT exp claims are typically seconds. Convert them before you decide a session is expired. Application logs may mix both units; label the field in your own code.

Related tools

• Timestamp converter
• UUID generator for request IDs next to timestamps