Unix Timestamp Converter

What Is a Unix Timestamp?

A Unix timestamp is a single number representing a moment in time: the count of seconds (or milliseconds) since the Unix epoch. Because it is just arithmetic on one value, timestamps compare, sort and diff trivially, which is why virtually every API, database and log format stores them this way. The only catch is that they are meaningless to humans at a glance — which is exactly what this tool converts.

The 1970 epoch

The origin of the count is 00:00:00 UTC on January 1, 1970. Values for dates before that day are negative. The epoch was fixed by the original Unix implementations and became a de-facto standard for computing; the ISO calendar and other systems keep their own origins, but Unix time is the one you see in the wild.

Seconds vs milliseconds

The original convention counts seconds — a 2026 timestamp looks like 1758614400 (10 digits). JavaScript's Date, Java, Python's time.time_ns() and most databases work in milliseconds (13 digits, 1,000× larger) to keep sub-second precision. When a number is "ten times too big", it is almost certainly milliseconds; this tool accepts both — the 13-digit input is detected automatically.

Time zones: it is all UTC

A timestamp does not carry a time zone; it is one instant on the timeline. ISO 8601 output in this tool is therefore written in UTC with a trailing Z, which removes all ambiguity. The calendar date and time you see in the input fields are rendered in your device's local time zone, since that is how you will reason about them.

Frequently Asked Questions

Debugging a live payload? Shift an instant forward or back in the Date Adder and dig the timestamps out of the query string with the URL Parser.