What it does
A Unix timestamp counts the seconds since midnight UTC on 1 January 1970. Logs, databases and APIs store dates this way: one number, no time zone. This page turns that number into dates people can read, and turns a date back into a number.
It uses your device’s clock and the time zone rules built into your browser, and sends nothing anywhere. Version 7 IDs from the UUID generator carry a millisecond timestamp you can read here.
How to use it
- Type or paste a timestamp in the top box, or press Now for the current time.
- Pick a time zone under Also show in to add that zone’s time to the table.
- To go the other way, pick a date and time under Date to timestamp and say which zone that time is in.
Clear empties both boxes.
What each setting does
- Unit: Auto reads 11 digits or fewer as seconds and 12 or more as milliseconds (today’s times are 10 digits in seconds, 13 in milliseconds). Choose Seconds or Milliseconds to override it. Spaces and commas are ignored; negative numbers are before 1970.
- Also show in: any IANA time zone your browser knows, such as Asia/Kolkata or America/Toronto. The table shows the wall time there and its offset from UTC, including daylight saving.
- This time is in: whether the date you picked is UTC, your own zone, or the zone chosen above.
The table gives Unix seconds and milliseconds, ISO 8601 in UTC, RFC 2822 (the email date format), the time in UTC, in your zone and in the chosen zone, and a relative time such as “3 days ago”. Months in the relative time count as 30.4 days.
Worked example
Type 1700000000. It is read as seconds (10 digits) and shows ISO 8601 2023-11-14T22:13:20Z and RFC 2822 Tue, 14 Nov 2023 22:13:20 +0000. In Asia/Kolkata (UTC+05:30) that is 03:43:20 on 15 November.
Type 1700000000000 instead: Auto sees 13 digits, reads it as milliseconds, and shows the same moment.
Going back, 2023-11-14 22:13:20 in UTC gives 1700000000. The same wall time in Asia/Kolkata gives 1699980200, which is 19,800 seconds (5 hours 30 minutes) earlier.
FAQs
Does it count leap seconds? No. Unix time skips them, as computers do.
What about the year 2038 problem? It affects programs that store seconds in 32 bits. This page does not, so dates past 2038 work.
Where the numbers come from
- Unix time as in POSIX (IEEE Std 1003.1); date formats from ISO 8601 and IETF RFC 2822; time zone rules from the IANA tz database built into your browser. fibub's own working.
Standard scientific values, such as constants, atomic weights and melting points, are facts found in every textbook; we name where ours were checked. If you are an author or publisher and want a value, a credit or a table changed or removed, tell us and we will act quickly.
Last updated 2026-11-10.