Timestamp Converter
Convert a human date/time to and from a Unix timestamp.
🔒 Runs entirely in your browser — nothing is uploaded.
How Timestamp Converter works
How does the timestamp converter work?
Converting from a date, it reads your local <input type="datetime-local"> value into a JavaScript Date and divides its epoch milliseconds by 1000. Converting from a pasted number, it counts the digits you typed - more than 10 digits is treated as milliseconds, 10 or fewer as seconds - then builds ISO 8601, UTC, local, and millisecond outputs from the resulting Date object.
When would I use it?
It is handy for converting a Unix timestamp stored in a database row or returned by an API into a readable date, or the reverse when constructing a query or request that expects epoch time.
How reliable is the seconds-vs-milliseconds detection?
It is a simple digit-count heuristic rather than a date-range check, so it works correctly for essentially every real-world timestamp today - 10-digit seconds versus 13-digit milliseconds - though it is not foolproof at the extreme edges, like a malformed 9- or 11-digit value.