Unix Timestamp Converter
Convert Unix timestamps to readable dates and back.
Runs locally in your browser. Your input is not uploaded or stored. You can verify this in your browser’s network panel.
What does this tool solve?
Convert among ten date/time formats used by IT Tools: JavaScript locale date string, ISO 8601, ISO 9075, RFC 3339, RFC 7231, Unix seconds, Unix milliseconds, UTC, Mongo ObjectID, and Excel date/time.
What examples should you start with?
Seconds to date
Input
1736899200
Output
2025-01-15T00:00:00.000Z
Milliseconds to date
Input
1736899200000
Output
2025-01-15T00:00:00.000Z (same instant, milliseconds unit)
Date to timestamp
Input
2025-01-15T00:00:00Z
Output
1736899200 (seconds) · 1736899200000 (milliseconds)
How does it work?
The selected input format parses one instant, then every supported format is rendered from that same date. When the input is empty, the current time is used.
All formatting happens in your browser. Local formats use the device timezone; Unix timestamps use seconds or milliseconds since the Unix epoch.
What are the edge cases and limits?
- Negative Unix timestamps are valid and represent dates before 1970.
- The format selector controls ambiguous numeric input; detected formats are selected automatically for pasted values.
- JavaScript dates are limited to roughly ±275,760 years; values beyond that return an explicit error rather than an Invalid Date.
- Leap seconds are not representable: Unix time assumes every day has exactly 86,400 seconds.
Technical reference
Related tools
- Timezone ConverterConvert times between IANA timezones with DST handled.
- Date Difference CalculatorCalculate the exact duration between two dates and times.