How to use Unix Timestamp Converter
- Choose Timestamp to date or Date to timestamp.
- For numbers, explicitly choose seconds or milliseconds. For a date, choose UTC or your browser’s local timezone.
- Read the live UTC, local, ISO, and numeric results. Current timestamp fills in the present instant.
A closer look
Unix time measures elapsed time from January 1, 1970 at 00:00:00 UTC. A value in milliseconds is 1,000 times the equivalent seconds value, so choosing the wrong unit produces a very different date. For example, 1700000000 seconds corresponds to 2023-11-14T22:13:20.000Z. ISO output ends with Z to mark UTC. Local output represents that same instant using the device’s timezone rules. Negative timestamps before 1970 are accepted within the supported years 0001–9999.
A practical example
Choose seconds and enter 0 to see 1970-01-01 at 00:00:00 UTC. Select milliseconds explicitly when your source uses a millisecond timestamp.
A useful tip
During daylight-saving changes, a local clock time can be missing or occur twice. Missing local times are rejected; for repeated times the browser selects the earlier occurrence. Use UTC to avoid this ambiguity.
Good questions. Simple answers.
Does the tool guess seconds versus milliseconds?
No. You choose the unit explicitly, so short or historical timestamps are not misclassified by digit count.
Can I keep fractional seconds?
Yes, up to whole-millisecond precision. Dates are represented with the browser Date API, which does not model leap seconds separately.
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