Unix Timestamp Converter Guide: Seconds, Milliseconds, UTC, and Local Time
Learn how Unix timestamps work, why seconds and milliseconds get confused, and how to convert API, log, and JWT dates safely.
Browser-only utility
Unix Timestamp Converter, private by default
Paste epoch seconds, epoch milliseconds, or an ISO date to convert between UTC, local time, and Unix formats without uploading values.
Convert Unix timestamps
Converted time
WaitingEnter a Unix timestamp in seconds or milliseconds.
Epoch seconds
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Epoch milliseconds
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UTC ISO
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Local time
Waiting
Relative
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Detected input
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Timestamp conversion runs locally in your browser and does not upload pasted values to tempboxs.
How to use timestamp converter safely
What Unix timestamps represent
A Unix timestamp counts time from 1970-01-01T00:00:00Z. Many APIs, databases, logs, and authentication tokens use this format because it is compact and easy for machines to compare.
The most common confusion is unit size. Traditional Unix timestamps are in seconds, while JavaScript Date values and many frontend logs use milliseconds.
Seconds, milliseconds, UTC, and local time
The same instant can be displayed differently depending on timezone. UTC is the neutral reference used by servers and logs, while local time is what your browser displays for your current region.
When debugging production events, compare UTC values first. Use local time only when you need to connect the timestamp to what a person saw on their device.
- 10-digit values are usually epoch seconds
- 13-digit values are usually epoch milliseconds
- ISO strings ending in Z are expressed in UTC
- JWT exp, iat, and nbf claims are usually seconds
Private debugging workflow
Paste the smallest timestamp or date value needed, check the converted UTC and local time, then copy the result into your notes, support ticket, or test case.
Because the conversion happens in your browser, the tool is a good fit for logs, token claims, or support snippets that should not be uploaded to random converters.
Why people use this tool
Timestamps and dates are converted locally in your browser. tempboxs does not receive pasted values.
Seconds and milliseconds
Detect common Unix seconds and JavaScript millisecond timestamps automatically.
UTC and local output
See ISO UTC, local browser time, epoch seconds, epoch milliseconds, and relative timing together.
Useful for tokens and logs
Translate JWT exp, iat, nbf claims, API logs, webhook payloads, and database timestamps quickly.
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FAQ
No. Timestamp conversion runs locally in your browser and does not send pasted values to tempboxs.
Most 10-digit Unix timestamps are seconds, while 13-digit values are usually milliseconds. The converter detects the common format automatically.
UTC is a global reference time. Local time applies your browser's timezone offset, so the same instant can appear as a different clock time.
Yes. JWT exp, iat, and nbf claims are usually epoch seconds, so you can paste those values to read the corresponding UTC and local times.