How it works
Unix time counts whole seconds since 00:00:00 UTC on January 1, 1970 (the "epoch"). Negative numbers represent instants before 1970; the converter accepts both seconds and milliseconds.
Unix Timestamp Converter
Convert Unix time to a date, or a date to Unix time.
Interactive calculator
This calculator becomes interactive when JavaScript is available. The page still provides its method, limits and related tools without JavaScript.
Result classification
Standard-based. The result follows a published technical standard or the browser’s IANA time-zone data. Browser time-zone data can vary by version, so important historical or future rules should be confirmed.
Limitations
Depends on the browser’s standards and time-zone database version. Repeated or nonexistent local times require an explicit choice.
Frequently asked questions
Why do I see two different "large" numbers for the same date?
One value is likely in seconds and the other in milliseconds. A millisecond timestamp is 1,000 times the corresponding seconds value.
Practical guide
Reviewed 27 July 2026How to use the Unix Timestamp Converter
- Enter the known values.Use the date, time, place or duration requested above.
- Check the assumptions.Confirm time zone, weekend, inclusion and rounding choices when shown.
- Read and reuse the result.Copy, share or continue to a related tool without retyping unnecessary information.
Common uses
The Unix Timestamp Converter is useful for logs, APIs, databases, debugging and data interchange.
Edge cases to check
Pay particular attention to seconds versus milliseconds, UTC versus local display and dates before 1970.