Convert an integer Unix timestamp into both UTC and your browser's local time. Choose seconds or milliseconds explicitly, or enter a local date and time to obtain both epoch units. This is useful when checking API responses, application logs and JWT time claims.
lightbulb When to use this tool
- check_circle Check whether an API value uses Unix seconds or JavaScript-style milliseconds.
- check_circle Compare a server log timestamp with a local event without confusing UTC with local time.
- check_circle Inspect exp, iat or nbf numbers from a decoded JWT; decoding time claims does not authenticate the token.
Inputs and results
Input: An integer Unix timestamp with the matching seconds or milliseconds unit, or a date/time interpreted in your browser's local timezone.
Output: UTC and local date displays for a timestamp; seconds and milliseconds with copy controls for a local date.
Why use our tool?
Compare UTC and local time
The same timestamp appears in UTC and local time for a direct comparison.
Select the right unit
An explicit unit selector avoids relying on the number of digits alone.
Copy either timestamp unit
Date-to-timestamp conversion shows seconds and milliseconds together.
How it works
Paste the integer timestamp under Unix to Human Date.
Select Seconds or Millis to match the source system's documentation.
Read the UTC result and local result as two displays of the same instant.
To convert the other way, enter a date/time in Human Date to Unix. It is interpreted in your browser's timezone; copy the required unit.
Use Get Current Timestamp for a current-time starting point, then confirm the unit before copying into another system.
Examples
science The Unix epoch
Enter 0 with Seconds selected. UTC is Thu, 01 Jan 1970 00:00:00 GMT. Local time may show a different clock time or calendar date, depending on your timezone.
science Seconds and milliseconds describe the same instant
1700000000 seconds and 1700000000000 milliseconds both represent 14 November 2023 at 22:13:20 UTC. Milliseconds = seconds × 1000; whole seconds = floor(milliseconds ÷ 1000).
science Spot a unit mismatch
A recent 13-digit millisecond value pasted with Seconds selected will produce a far-future or invalid date. Change the selector to Millis and compare against the expected event date.
Limitations
The date/time input uses your browser's local timezone and has no separate timezone selector. Daylight-saving transitions can make a local time ambiguous or nonexistent. The Unix input expects integer seconds or milliseconds; microseconds and nanoseconds are unsupported. Unix timestamps do not themselves contain a timezone.
Frequently Asked Questions
How do I know whether a timestamp is seconds or milliseconds? expand_more
Why are UTC and local time different? expand_more
Does the date input mean UTC? expand_more
Does this converter support microseconds or nanoseconds? expand_more
Processing & Privacy
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