Unix Timestamp Converter
Convert a Unix timestamp in seconds or milliseconds into ISO 8601, UTC, and local time, or convert a date back into a timestamp.
Timestamp to date
The unit is guessed from the number of digits; change it if needed.
Date to timestamp
Current timestamp
How to convert Unix timestamps
Convert a Unix timestamp in seconds or milliseconds into ISO 8601, UTC, and local time, or convert a date back into a timestamp.
What a Unix timestamp is
A Unix timestamp counts the seconds (or milliseconds) that have passed since January 1, 1970, 00:00:00 UTC. It's the format most APIs, logs, and databases use to store a point in time without depending on any particular timezone or calendar format.
Seconds or milliseconds?
Today's timestamps in seconds have 10 digits, and the same moment in milliseconds has 13. This tool guesses the unit from how many digits you paste, and switches the toggle automatically; change it yourself if a value is ambiguous.
How to use it
- Paste a timestamp on the left to see it as ISO 8601, UTC, and your local time, or choose "Use current time" to fill in now.
- Pick a date and time on the right to convert it back into Unix seconds and milliseconds.
- The current timestamp panel updates every second, for a quick reference or to copy right now's value.
Local conversion
Every conversion runs in your browser using its built-in Date object. No timestamp or date you enter is sent to a ProntoUso server.
Unix timestamp converter FAQ
- Why does my timestamp show the wrong date?
- This usually means the unit is set incorrectly: a value meant to be milliseconds, read as seconds, lands about 1,000 times further in the future than intended, or the reverse. Toggle the unit and check again.
- What does the "Local time" field show?
- It shows the date and time in your device's own timezone and locale format, computed from the same underlying timestamp as the UTC and ISO 8601 fields.
- Can I convert a negative timestamp?
- Yes. A negative value represents a date before January 1, 1970, and is handled the same way as a positive one.
- Is the date or timestamp I enter sent anywhere?
- No. All conversion happens locally using your browser's own date handling.