Unix Timestamp Converter
Paste a timestamp to read it as a date, or set a date and time to get the timestamp back.
- Input
- Timestamp · date
- Output
- Date · timestamp
- Processing
- In your browser
- Cost
- Free · no sign-up
Timestamp → date
Ten digits is normally seconds; thirteen is normally milliseconds. Detect chooses from the size of the number and always says which it picked.
Date → timestamp
That instant
Live- ISO 8601 (UTC)
- —
- UTC
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- Your device's clock
- —
- Time zone
- —
- Day
- —
- Relative
- —
- Seconds
- —
- Milliseconds
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"Now" and the local reading both come from this device's own clock. If that clock or its time zone is set wrongly, the readings follow it.
Your data is processed locally in your browser and is never sent to Nekhen.
About this tool
A Unix timestamp counts the seconds since midnight UTC on 1 January 1970. It appears in log files, database rows, API responses and JSON Web Tokens, because a single integer has no time zone and no formatting to argue about.
The two things that make timestamps confusing are handled explicitly here. Seconds and milliseconds look identical — both are just a long number — so the tool decides from the magnitude, tells you what it decided, and lets you override it. And a wall-clock time means nothing without a zone, so UTC and your own device’s zone are always shown together rather than one silently standing in for the other.
Steps
How to use it
- Paste a timestampA number in seconds or milliseconds, or an ISO 8601 date.
- Check the unitThe tool states which it assumed. Set it yourself if the guess is wrong.
- Read the resultISO 8601, UTC, and the same instant on your own clock, each labelled.
- Or go the other waySet a date and time in the lower panel and read the timestamp back.
Real situations
Common uses
- Reading the `iat` or `exp` field out of a JSON Web Token
- Working out what time a log line was actually written, in your own zone
- Producing the exact integer an API wants for a "since" parameter
- Checking whether two systems recorded the same event at the same instant
Privacy
Files are processed locally in your browser and are never uploaded to Nekhen. Every calculation runs on your own device, so we never receive the contents of your file, never store it and never log it. Closing the tab clears everything from memory. More detail on the privacy page.
Common questions
Frequently asked
How do I tell seconds from milliseconds?
By size. A current timestamp in seconds is ten digits; in milliseconds it is thirteen. The tool uses that and shows which one it assumed, because reading milliseconds as seconds silently produces a date thousands of years out.
Which time zone are the results in?
Both of the ones that matter, side by side and labelled. ISO 8601 and the UTC line are absolute. The local line is the same instant on this device’s clock, with the zone name and the offset that applied on that date — so a summer timestamp reports the summer offset.
Does it handle dates before 1970?
Yes. Timestamps before the epoch are negative, and negative values convert normally in both directions.
Why does "now" not match my watch?
The current time is read from your device’s own clock. If the device clock is wrong or its time zone is set incorrectly, this tool will faithfully report that — it has no separate source of time to correct it with.
Is anything sent to a server?
No. Every conversion is arithmetic done in your browser using the time zone database the browser already carries. Nothing you enter is transmitted.
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