Epoch trivia
Timestamps are more fun than they have any right to be
People have thrown parties for a number. On 13 February 2009 the clock read 1234567890 and developers gathered in a dozen cities to watch it tick over.
Signed 32-bit time runs out on 2038-01-19T03:14:07Z
Does this affect me?
At that instant a time_t holding 2,147,483,647 increments once more and wraps to −2,147,483,648, which reads as 1901-12-13T20:45:52Z. Modern 64-bit systems are fine; the exposure is embedded firmware, old filesystem formats, 32-bit database columns and any protocol that pinned the field at four bytes.
Why a count of seconds has a history
Unix time is a plain count of seconds since the start of 1970, in UTC. Almost every computer, phone and server keeps time this way under the hood. Because it is just a number, it has round numbers, lucky numbers and limits, and people notice them.
The best known limit is 2038. Old systems store the count in a signed 32-bit number, and that runs out at 03:14:07 UTC on 19 January 2038. One second later it wraps round to 1901. The countdown at the top of this page ticks towards that moment. Most modern systems use 64 bits now, but old file formats, databases and small devices still carry the risk.
The page also lists the landmark values worth knowing by heart, the fun numbers still to come, and the facts about time that trip up careful code. There is a short history of leap seconds, too. Unix time pretends they do not exist, which is why a Unix day is always exactly 86,400 seconds.
Enter your birth date to see how many seconds you have been alive, then share the number with a link that opens on the same date.
Questions people ask
What happens in 2038?
Software that keeps Unix time in a signed 32-bit number runs out of room at 03:14:07 UTC on 19 January 2038. The next second reads as December 1901. It is the same kind of bug as Y2K, and it is fixed by moving to 64-bit time.
Why does Unix time start in 1970?
It was a round, recent date when Unix was being built at Bell Labs around 1970. It was picked for convenience, not for any deeper reason, and it stuck.
Does Unix time count leap seconds?
No. Every Unix day has 86,400 seconds. When a leap second is added, the clock repeats or smears a second instead, so the count stays in step with the calendar.
When was the 1234567890 party?
On 13 February 2009, at 23:31:30 UTC. Developers around the world met up to watch the counter roll past it.