About Unix timestamp converter
Use the Unix timestamp converter when a log, API, or database stores time as an epoch number. You can convert Unix milliseconds to date or start from seconds or an ISO date. Select the input unit explicitly: milliseconds and seconds represent different numbers for the same instant.
How to convert a Unix timestamp to an ISO date
- Choose Unix seconds, Unix milliseconds, or ISO date as the input format.
- Enter the value; include Z or an explicit offset for an unambiguous ISO input.
- Select Process and review the ISO, seconds, and milliseconds values together.
A practical example
- Input
0
- Result
ISO 8601: 1970-01-01T00:00:00.000Z Unix seconds: 0 Unix milliseconds: 0
With Unix seconds selected, zero represents the Unix epoch in UTC.
Supported input and limitations
- The numeric input is interpreted using the selected unit; there is no automatic unit detection.
- ISO output is UTC. Dates must fit the JavaScript Date range, and this tool does not model leap seconds.
Processing happens on your device. Read about local processing and optional workspace recovery.
Frequently asked questions
Are Unix timestamps in seconds or milliseconds?
Both conventions are common. Unix time traditionally counts seconds, while JavaScript often uses milliseconds. Check the source system and choose the matching input format.
Does a Unix timestamp include a timezone?
It represents an instant relative to the UTC epoch. A timezone is used when formatting that instant for local display; it is not embedded in the number itself.