Unix timestamp converter
Paste a timestamp or a date, get every other form of it. Seconds, milliseconds and microseconds are detected for you.
Questions people ask
Is my number in seconds or milliseconds?
Length tells you, and the tool works it out automatically: a 10-digit Unix timestamp is seconds, 13 digits is milliseconds, 16 is microseconds. Paste any of them and it reports which one it detected before converting.
What is a Unix timestamp?
The number of seconds elapsed since 1 January 1970 at 00:00 UTC, ignoring leap seconds. It is how computers usually store an instant, because it is a single number carrying no time zone with it — which is exactly why you need a converter to read one.
Is anything uploaded?
No. Every conversion is arithmetic performed in your browser with the built-in Date and Intl APIs. The uploads counter in the top bar stays at 0.
Can I go the other way?
Yes. Type a date in almost any common format, or use the picker, and you get the Unix timestamp in seconds and milliseconds along with ISO 8601, RFC 2822, the ISO week number and the day of the year.
Does it work offline?
Yes — including the time zone conversions, which use data already built into your browser.
How this works & why it’s private
Detection is by magnitude: the number of digits tells you whether you are looking at seconds, milliseconds or microseconds, because each unit lands in a distinct range for any date in the plausible past or future. From there everything is the browser's own Date object, plus Intl.DateTimeFormat for the time zone rows — that time zone database ships with your browser, which is why the conversions keep working with no connection. Nothing is sent anywhere; open your dev-tools Network tab and watch while you convert.