What is a Unix timestamp?
A Unix timestamp is the number of seconds since midnight (12:00:00 AM) UTC on 1 January 1970, not counting leap seconds. It names one exact moment as a single number, the same everywhere on Earth.
Action level No action usually needed
- Why you are seeing it
- It is a long number, often 10 or 13 digits, in software, web services and data files.
- Why it matters
- It names one exact moment as a single number, the number of seconds since 1 January 1970 UTC, the same everywhere on Earth.
- What should I do?
- Check whether the number counts seconds or milliseconds: a 10-digit value is almost always seconds and a 13-digit value milliseconds.
- Convert it to a clock time in the time zone you need, because the number itself has no time zone.
- A common misunderstanding
- The number itself has no time zone: the same timestamp shows different clock times in New York and London.
Turn a timestamp into a date
Try the example, or paste your own timestamp.
2023-11-14 10:13:20 PM UTC
- UTC
- 2023-11-14 10:13:20 PM (UTC)
- New York
- 2023-11-14 5:13:20 PM (EST, UTC-05:00)
- Counted in
- seconds (worked out from the number of digits)
- A Unix timestamp counts the time since 1 January 1970 at 00:00 UTC. It is the same moment everywhere; only the clock time you read it as changes with the time zone.
A simple example
The timestamp 1700000000
In UTC it is 2023-11-14 10:13:20 PM.
In New York that same moment is 2023-11-14 5:13:20 PM (EST).
The timestamp 0 is 1 January 1970 at 12:00:00 AM UTC.
Time zones
The number itself has no time zone. It points at one moment. A time zone only appears when you turn the number into a clock time, which is why the same timestamp shows different clock times in New York and London.
Seconds or milliseconds
Unix tools count seconds. JavaScript and many web services count milliseconds, which makes the number 1,000 times bigger. For dates in recent decades, a 10-digit value is almost always seconds and a 13-digit value milliseconds.
The year 2038 problem
Some older systems store the count of seconds in a signed 32-bit number, which runs out at 2,147,483,647. That moment is 3:14:07 AM UTC on 19 January 2038. Systems that store the count in 64 bits do not have the limit.
Try these tools
- Unix Timestamp ConverterTurn a Unix timestamp into a date, or a date into a timestamp.
Want more detail? Read the longer guide: What is a Unix timestamp, and how do you convert one to a date?