A Unix timestamp (also known as Epoch time or POSIX time) is the number of seconds that have elapsed since January 1, 1970, at 00:00:00 UTC — the Unix epoch. It is widely used in programming, databases, and systems to represent time in a simple, unambiguous numeric format that is timezone-independent.

The Unix epoch is January 1, 1970, 00:00:00 UTC. This is the reference point from which all Unix timestamps are measured. A timestamp of 0 corresponds to exactly this moment. Timestamps before this date are represented as negative numbers (e.g., -86400 = Dec 31, 1969).

Seconds (10 digits) is the standard Unix timestamp format used in most systems, APIs, and databases. Milliseconds (13 digits) is commonly used in JavaScript (Date.now()) and some logging systems for higher precision. Our tool auto-detects the format, but you can manually override it. When in doubt, if your timestamp has 10 digits it's seconds; 13 digits = milliseconds.

The Year 2038 problem affects 32-bit systems that store Unix timestamps as signed 32-bit integers. The maximum value a signed 32-bit integer can hold is 2,147,483,647, which corresponds to January 19, 2038, at 03:14:07 UTC. After this moment, the timestamp overflows and wraps around to negative values, potentially causing system failures. Modern 64-bit systems are not affected by this limitation.

Unix timestamps are always UTC-based — they represent a single, unambiguous moment in time regardless of timezone. This is one of their key advantages: you can store a timestamp and convert it to any local timezone when displaying it to users. Two timestamps that differ by 3600 represent times exactly one hour apart, no matter where in the world you are.

In different programming languages:
JavaScript: Math.floor(Date.now() / 1000) (seconds) or Date.now() (milliseconds)
Python: import time; int(time.time())
PHP: time() (seconds) or microtime(true) (float with microseconds)
Bash: date +%s
MySQL: SELECT UNIX_TIMESTAMP();
Or simply use the live clock at the top of this page!