Seconds, milliseconds or more
A Unix timestamp counts from midnight UTC on 1 January 1970. A number is read as seconds unless it is too large to be a date in seconds, in which case it is read as milliseconds (13 digits, as JavaScript and Java use), microseconds (16) or nanoseconds (19). The line under the box says which it chose; pick Seconds or Milliseconds to say yourself.
Dates to timestamps
Type a date such as 2026-10-14T09:30:00Z to go the other way. It is read in UTC when it ends in Z or an offset like +02:00, and in your own time zone when it does not. A date with no time, such as 2026-10-14, is read as midnight UTC. Now fills in the current time.
Seven ways to write it
The answer is shown as Unix seconds, Unix milliseconds, ISO 8601 in UTC and in your time, a written-out date in UTC and in your time zone, and how long ago or how far ahead it is, each with its own copy button.
Questions
Why does my timestamp come out in 1970, or thousands of years ahead?
It is being read in the wrong unit: milliseconds read as seconds land far in the future. Pick Seconds or Milliseconds to read it as the right one.
What is the year 2038 problem?
Systems that store Unix time as a signed 32-bit number run out at 2147483647, which is 03:14:07 UTC on 19 January 2038. This page works in larger numbers and reads dates far beyond it.
Does Unix time count leap seconds?
No. Every Unix day is exactly 86,400 seconds, so a leap second does not get a timestamp of its own.