Unix Timestamp Converter

Yes — the tool detects which one you entered by digit count (10 digits = seconds, 13 = milliseconds) and converts accordingly.

The 'Local' result uses your browser's timezone. UTC and ISO 8601 are timezone-independent, so use those when sharing a timestamp with someone in a different timezone.

Yes — it uses the browser's native Date object, the same one your code likely uses, so conversions match exactly.