03 / DEVELOPER
Timestamp Converter
Parse Unix seconds, milliseconds or ISO-8601 strings and view the same instant in Unix s/ms, ISO UTC and your local timezone.
How to use
- 1Paste a Unix timestamp (seconds or milliseconds) or an ISO-8601 string into the input.
- 2The four result cards show the same instant as Unix s/ms, ISO UTC, and your local time.
- 3Click Now to fill the input with the current moment.
- 4Use Copy on any card to grab that representation.
Frequently asked questions
How do you tell seconds from milliseconds?
Heuristic: any all-digit number with 13 or more digits is treated as milliseconds; 10-digit values are treated as seconds. Anything else is parsed as ISO-8601.
What timezone does Local time use?
Whatever your browser reports — usually your operating system's timezone. The label includes the IANA name when available.
Are negative timestamps (pre-1970) supported?
Yes. Both inputs and outputs handle dates before 1970-01-01.
Is the conversion sent anywhere?
No. Parsing and formatting use the browser's built-in Intl APIs — entirely local.
Does it handle ISO strings without a timezone?
Yes, but they're treated as local time per the JavaScript spec. Add a 'Z' suffix if you mean UTC.