Unix timestamp converter
Paste a Unix timestamp to see the date in your time zone and UTC, or pick a date to get its timestamp, in seconds and milliseconds.
Free · no signup Runs in your browser
Date to timestamp
How do I convert a Unix timestamp to a date?
Paste the timestamp. Numbers of 11 digits or more are read as milliseconds and shorter ones as seconds, or you can choose the unit. The tool shows the ISO 8601 date, the date in your own time zone, the UTC date and how long ago or from now it is. To go the other way, pick a date and time and read its timestamp.
What a Unix timestamp is
A Unix timestamp counts the seconds that have passed since midnight at the start of January 1, 1970, UTC, known as the Unix epoch. Computers like it because it is a single number that does not depend on time zones, calendars or daylight saving, and two timestamps can be compared or subtracted directly. Many programs and databases also use milliseconds, which is the same count multiplied by 1,000, so a timestamp with 13 digits is almost always in milliseconds.
The tool displays each timestamp in three ways: as an ISO 8601 date in UTC, as a date in the time zone of your device, and in the plain UTC form. Showing both zones is useful when you are debugging a log written on a server in another zone. The current time in seconds and milliseconds is shown at the top and updates every second.
It runs in your browser. Nothing you enter is sent anywhere.
How it works in detail
A Unix timestamp is the number of seconds since 1970-01-01 00:00:00 UTC. The tool reads your number and shows the date as ISO 8601, in your own time zone and in UTC. On Auto, a number with 11 digits or more is read as milliseconds (13 digits for dates in our era) and a shorter one as seconds; you can choose the unit instead. In the other direction you type or pick a date and time, say whether it is in your time zone or UTC, and get the timestamp in seconds and milliseconds. It uses the browser's Date object, which counts milliseconds from the Unix epoch and can represent dates roughly 270,000 years either side of 1970. Leap seconds are not counted in Unix time, so a Unix day is always 86,400 seconds. The local time zone is whatever your device is set to.
How to use it
- Paste a Unix timestamp and leave the unit on Auto, or choose seconds or milliseconds.
- Read the date in ISO 8601, in your time zone and in UTC.
- To go the other way, enter a date and time and choose whether it is in your time zone or UTC.
- Copy the timestamp in seconds or milliseconds.
- Check the time zone if two systems give different times.
What changes and what stays the same
What the tool does with your input, and what it leaves alone.
| Aspect | What happens |
|---|---|
| The moment in time | The same moment shown in different forms |
| Time zone | Shown in your device's zone and in UTC |
| Leap seconds | Not counted in Unix time |
| Range | Roughly 270,000 years either side of 1970 |
| Precision | Milliseconds |
| Privacy | Everything is worked out in your browser; what you type or choose is not uploaded or saved |
When to use it
- Reading a timestamp from a log, an API or a database
- Setting an expiry time for a token or a cookie
- Working out how long ago something happened
- Converting a date to a timestamp for a query
Problems you may run into
Most problems come from the input, not from the tool.
| What you see | Likely cause | What to do |
|---|---|---|
| The date is in 1970 | A timestamp in milliseconds was read as seconds, or the reverse | Choose the unit instead of Auto |
| The date is far in the future | A timestamp in seconds was read as milliseconds | Set the unit to seconds |
| The time is a few hours off | A different time zone | Compare the UTC line, which does not depend on a zone |
| Daylight saving shifts a time | Local time changes twice a year in many places | Use UTC for anything that must be exact |
| Negative timestamps | They are dates before 1970 | That is valid; the tool shows them |
| Nothing happens after I paste | The box is empty, or the text was copied as an image | Copy the text again from the source and paste it into the box |
Mistakes it helps you avoid
- Reading a milliseconds value as seconds, which gives a date thousands of years away.
- Forgetting the time zone: a timestamp is UTC, and the same moment is a different clock time in each zone.
- Entering a local date but expecting UTC, or the reverse: choose the zone.
- Expecting a negative timestamp to fail: dates before 1970 are negative numbers.
How it works
Everything happens in your browser as you type.
timestamp (seconds) = seconds since 1970-01-01 00:00:00 UTCtimestamp (milliseconds) = seconds × 1,000 (13 digits for dates in our era)a number of 11 digits or more is read as milliseconds when the unit is on Autodate = new Date(milliseconds), shown as ISO 8601, in your time zone and in UTC
The tool uses the browser's Date object, which counts milliseconds from the Unix epoch and can represent dates roughly 270,000 years either side of 1970. Leap seconds are not counted in Unix time, so a Unix day is always 86,400 seconds. The local time zone is whatever your device is set to.
Example: one billion seconds
You convert the timestamp 1000000000.
- Seconds since the epoch1,000,000,000
- UTC date2001-09-09 01:46:40
2001-09-09T01:46:40.000Z
In Toronto that moment was the evening of 8 September, because of the time zone.
Terms on this page
- Unix epoch
- Midnight UTC at the start of January 1, 1970, the starting point of Unix time.
- ISO 8601
- The standard way to write dates and times, such as 2026-10-25T14:30:00Z.
Common questions
What is the Unix epoch?
Midnight at the start of January 1, 1970 in UTC, the moment from which Unix time counts seconds.
How do I tell seconds from milliseconds?
A current timestamp in seconds has 10 digits and in milliseconds 13. The tool reads 11 digits or more as milliseconds when the unit is Auto.
Why does my date look an hour or more off?
The timestamp is in UTC, and the tool shows your local time as well. The two differ by your time-zone offset.
Can timestamps be negative?
Yes. Negative numbers are dates before 1970.
Is my data uploaded?
No. The conversion happens in your browser.
Where these numbers come from
- MDN Web Docs — Date How a browser represents dates as milliseconds since the epoch.
- Open Group — POSIX definition of seconds since the Epoch The definition of Unix time.
- W3C — Date and Time Formats (ISO 8601 profile) The ISO 8601 form shown in the result.
Last verified 2026-10-25 The method on this page is checked against the sources above at least once a year. Spotted something out of date? Tell us and we will fix it.
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