Unix Timestamp Converter

What a Unix timestamp actually counts

A Unix timestamp, also called epoch time, counts the number of seconds that have passed since midnight UTC on January 1, 1970. It is timezone free by design: the same number means the same exact instant everywhere in the world, which is why databases, log files and APIs use it internally instead of a formatted date string.

Seconds versus milliseconds

Some systems, like most Unix and database timestamps, use seconds. Others, like JavaScript's Date.now() and many JSON APIs, use milliseconds. This tool detects which one you likely entered by checking the size of the number: a value of 1,000,000,000,000 or larger is treated as milliseconds, since a seconds based timestamp would need to be over 30,000 years in the future to reach that size.

Why this matters for logs and analytics

Getting the units wrong is one of the most common timestamp bugs: treating a millisecond value as seconds pushes the resulting date back by a factor of a thousand, landing somewhere in the 1970s instead of the correct year. This converter shows both the UTC time and your local time side by side so you can immediately sanity check whether the value you are looking at, from a server log, a webhook payload or a database column, actually lines up with when you expect the event to have happened.