Unix timestamp converter

How it works

1. Enter a Unix timestamp and choose automatic, seconds or milliseconds.
2. Convert it to see ISO 8601, UTC-equivalent and browser local time.
3. Alternatively choose a local date and time to create seconds and milliseconds.
4. Use Current timestamp only when you want a fresh value.

Practical example

0 seconds represents 1970-01-01T00:00:00.000Z. A 13-digit value such as 1724140800000 is normally milliseconds rather than seconds.

Formula and explanation

Unix time counts elapsed time from 1 January 1970 at 00:00:00 UTC. Seconds are common in server APIs, while JavaScript Date and many logs use milliseconds.

Automatic mode treats values with at least twelve significant digits as milliseconds. Select the unit explicitly for historic, negative or unusual values where magnitude-based detection could be ambiguous.

ISO 8601 output ends in Z and represents UTC. Local time is formatted using this browser's timezone. The current value is captured only after pressing its button, avoiding a constantly updating component and hydration differences.