Unix Timestamp

Convert timestamps and dates

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About this tool

This tool converts between a Unix timestamp and a human-readable date and time. It automatically detects seconds versus milliseconds based on the number of digits you enter, and shows ISO 8601, Korean local time, UTC, and relative time all at once.

How to use

  1. Type a number into the Unix timestamp field, or click 'set to now' to fill in the current time.
  2. Picking a date and time directly with the datetime-local input also updates the timestamp.
  3. Below, you get seconds, milliseconds, ISO 8601 (UTC), Korean local time, a UTC string, and the relative time from now.
  4. The live clock at the top shows the current Unix timestamp at all times.

Frequently asked questions

How does it tell seconds and milliseconds apart?
It goes by the digit count of what you type. 11 digits or fewer is treated as seconds and multiplied by 1000; 12 digits or more is treated as already being in milliseconds and used as-is.
What timezone is the ISO 8601 value in?
The ISO 8601 line is in UTC. The 'Korean time' line and the datetime-local input, on the other hand, are shown in whatever local timezone this browser is set to.
How is the relative time (e.g. "3 hours ago") calculated?
It takes the difference between the entered time and the current moment and rounds it to whichever unit โ€” seconds, minutes, hours, or days โ€” fits best. This value refreshes every second while the page is open.
Is the date/time I enter sent to a server?
No. Every conversion is computed with the browser's built-in Date object and never sent to a server.

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