Timestamp Converter
Convert Unix timestamps to dates and back.
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- Unix (seconds)
- Unix (milliseconds)
- ISO 8601
- UTC
- Your time zone
- Relative
- Day
About this tool
A Unix timestamp counts the seconds elapsed since the first moment of 1970 in UTC, which makes it compact, unambiguous and completely unreadable to humans. Converting between that number and a real date is a constant small chore when reading logs, debugging tokens or inspecting database rows. The awkward part is that a bare number is ambiguous: some systems count seconds and others count milliseconds, and reading one as the other drops you in 1970 or several thousand years into the future. This converter detects the unit automatically, since current values in the two systems differ by a factor of a thousand, and tells you which one it assumed so you can override it if the guess is wrong. It works in both directions, accepts ISO 8601 and ordinary date strings as input, and shows the result in UTC alongside your own time zone, because mixing the two up is the second most common cause of off-by-hours bugs. Everything is computed locally.
How to use it
- Paste a Unix timestamp, or type a date such as 2026-08-03T12:00:00Z
- Read the converted values in UTC and your local time zone
- Copy whichever format you need
Frequently asked questions
How does it know if my number is seconds or milliseconds?
By magnitude. A current timestamp in seconds is about ten digits, while the same moment in milliseconds is thirteen. Anything at or above one hundred billion is read as milliseconds. The tool tells you which it assumed so you can spot a wrong guess immediately.
Why does my timestamp show a different time than I expect?
Almost always a time zone difference. Unix timestamps are always UTC, with no zone information stored at all. The converter shows both UTC and your local time so you can see the offset directly rather than guessing.
Can I convert dates before 1970?
Yes. Timestamps before the epoch are negative, and negative values are handled normally. A date such as 1960 gives a large negative number, which is correct even though some systems reject it.
What is the year 2038 problem?
Systems storing timestamps in a signed 32-bit integer overflow in January 2038, roughly 2.1 billion seconds after the epoch. Modern systems use 64-bit values and are unaffected, but the limit still appears in older embedded software and legacy database columns.
Does it handle daylight saving time?
Yes, for the local display. The underlying timestamp is a fixed point in time with no concept of daylight saving, but converting it into a local time zone applies whatever offset was in effect on that date.