Unix Timestamp Converter
Convert between Unix timestamps and human-readable dates in local, UTC and ISO formats. Free developer tool.
Free · No sign-upHow to use Unix Timestamp Converter
- 1. Paste a Unix timestamp in seconds, milliseconds, microseconds or nanoseconds, an ISO 8601 or RFC 2822 date, or type “now” — the format is detected automatically.
- 2. Pick a time zone with the quick buttons (Local, UTC, New York, Chicago, Denver, Los Angeles, London and more) or search for any IANA zone name.
- 3. Copy any output with its button: seconds, milliseconds, ISO 8601, RFC 2822, the full date in your zone, relative time, ISO week or an Excel/Sheets serial.
- 4. Open Date & time → Unix timestamp to convert the other way, or Batch convert to paste up to 5,000 values and download the results as CSV.
Frequently asked questions
Is the Unix timestamp converter free, and can I convert timestamps in bulk?
Yes, it’s free with no sign-up. Besides single values, the Batch convert panel accepts up to 5,000 timestamps or dates, one per line, and exports the results — in UTC and your chosen time zone — as a CSV file.
Does the timestamp converter send my data anywhere?
No. Parsing, time-zone math and CSV export all run in your browser using its built-in time-zone data, so the log timestamps and dates you paste aren’t uploaded to or stored by GrabCast.
How do I convert a Unix timestamp to a date in Excel?
Excel and Google Sheets count dates as serial days, so a raw timestamp won’t display as a date. Paste it here and copy the Excel/Sheets serial output, or use =A1/86400+DATE(1970,1,1) in your sheet and format the cell as a date. Both give UTC unless you adjust for your time zone.
How can I tell if a timestamp is in seconds or milliseconds?
Count the digits: current dates are 10 digits in seconds, 13 in milliseconds, 16 in microseconds and 19 in nanoseconds. The converter detects this automatically and, for in-between lengths like 11 or 12 digits, also shows what the value would mean in the other unit.
How do I convert a Unix timestamp to another time zone with daylight saving time?
Choose the zone from the quick buttons or type an IANA name such as America/Chicago. The converter uses your browser’s time-zone database, so the correct daylight saving offset is applied for that exact date, and the ISO 8601 output includes the matching UTC offset.
Does the converter handle negative timestamps and dates before 1970?
Yes. Zero and negative Unix values are supported, so -86400 converts to December 31, 1969 UTC. You can also enter an ISO 8601 date such as 1965-07-04T12:00:00Z and get the matching negative timestamp in seconds and milliseconds.