Timestamp Converter
Paste a timestamp in any of the three common forms and read it back in all of them, in UTC and in your own time zone, with the offset spelled out. A ten-digit number is read as seconds and a thirteen-digit one as milliseconds, and Furtu tells you which reading it used and what the other one would have meant.
Detection is right for any current date. Pin it if you are working with something unusual.
How timestamp converter works
- Paste a timestamp or a dateSeconds, milliseconds or an ISO 8601 string.
- Read it back three waysUnix seconds, Unix milliseconds and ISO 8601, plus your local time.
- Check the zoneThe offset is spelled out, and the relative time is there when you need it.
What you get
Move between Unix seconds, milliseconds and ISO 8601 without guessing. Everything happens inside this page: the file is read by your browser, transformed in memory and handed straight back to you as a download. There is no upload queue, no waiting for a server, and nothing left behind when you close the tab.
Supported formats
This tool works on text you paste or type, so there is no file format to worry about. Nothing you type is sent anywhere.
Limitations, stated up front
- JavaScript dates run from 271821 BC to 275760 AD. A timestamp outside that range is reported rather than wrapped.
- A leap second has no representation in Unix time, so 23:59:60 on a leap day does not appear.
- Time zone names come from the browser, and a user can override them, so the local reading follows the machine rather than a fixed table.
Frequently asked questions
What is the difference between seconds and milliseconds?
The same instant, written with a different unit. 1767225600 and 1767225600000 are one moment. Mixing them up is the commonest timestamp bug, and it produces a date in 1970 or a date fifty thousand years out. Furtu shows both numbers for every input so the pair is never a mystery again.
How does it decide which one you meant?
By magnitude. Around ten digits is the current era in seconds; around thirteen is the current era in milliseconds. Furtu states the reading it used and gives the alternative, so a wrong guess is visible rather than silent. Pin the unit in the control when the guess is not good enough.
What is my time zone?
The one your browser reports, named explicitly with its current offset, which changes with daylight saving. UTC is always shown alongside it, because a timestamp without a zone is not a moment — it is a set of possible moments.
Can it read a date string?
ISO 8601, reliably, because it is a standard. Other formats are matched against the browser’s looser parser, which is not a standard and differs between browsers — Furtu warns when it falls back to that, so you know how much to trust the answer.
Is the timestamp I convert uploaded?
No. The conversion runs in your browser, so a timestamp taken from an internal system does not disclose anything about that system.