What is a Unix timestamp?
A Unix timestamp counts the number of seconds (or milliseconds) since January 1, 1970, 00:00:00 UTC — the "Unix epoch". It's timezone-independent: the number itself represents one exact instant, and only its human-readable display depends on which timezone you choose to view it in.
How to use this tool
Use Timestamp → Date to convert a Unix timestamp into a readable UTC and local date — the unit (seconds or milliseconds) is auto-detected from the number of digits, or you can pick it explicitly. Use Date → Timestamp to pick a date and time in your browser's local timezone and get both Unix seconds and milliseconds. The Current Unix Timestamp section shows right now's timestamp, refreshed on demand.
Example
The timestamp 0 converts to 1970-01-01 00:00:00 UTC.
FAQ
How does the tool know if my timestamp is seconds or milliseconds?
By digit count: 10 digits or fewer is treated as seconds (covers dates up to the year 2286), anything longer as milliseconds. You can override this with the unit selector.
Which timezone is the Date → Timestamp input in?
Your browser's local timezone, shown underneath the date picker.