Unix timestamp

A Unix timestamp counts the seconds since 1 January 1970 (UTC) and is the standard way computers store time - in log files, databases, APIs and cookies. For humans, though, such a long number is not readable. This tool translates both ways: you enter a timestamp and get the date in ISO 8601 notation (UTC), or you enter a date and get the matching timestamp.

The tool detects automatically what you enter. A plain number is read as a timestamp - distinguishing seconds from milliseconds (thirteen digits and up count as milliseconds). Anything else is parsed as a date. The output always shows both: the date in ISO 8601 (UTC) as well as the timestamp in seconds and in milliseconds, so you can take the value you need directly.

The whole conversion runs entirely locally in your browser in pure JavaScript - your input is not uploaded, not stored, and no foreign library is loaded from a CDN. The calculation is in UTC so the result is unambiguous and reproducible and does not depend on your device time zone.

Specifications

In 3 steps

1. Paste a timestamp or date into the text field.
2. Click convert.
3. Read the date (ISO 8601, UTC) and timestamp (seconds + milliseconds).

Limitations: The calculation is in UTC (world time), not your local time zone - that keeps the result unambiguous. Plain numbers of thirteen digits or more are treated as milliseconds, shorter ones as seconds. If the input is neither a valid timestamp nor a recognizable date, the tool says so honestly instead of guessing.

FAQ

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