What is a Unix timestamp (epoch time)?
A Unix timestamp is the number of seconds since 1970-01-01 UTC. Learn how epoch time works and convert a timestamp to a date free.
A Unix timestamp (epoch time) is the number of seconds that have elapsed since 00:00:00 UTC on 1 January 1970 — the "Unix epoch". It is the most common way computers store a moment in time, because it is a single number with no timezone ambiguity.
Why seconds since 1970
Representing time as one integer makes it trivial to store, compare, and do arithmetic on — "5 minutes later" is just +300. It is always in UTC, so there is no timezone confusion until you format it for a human. Many APIs, JWT exp claims, and databases store time this way.
Seconds vs milliseconds
Unix time is classically in seconds, but JavaScript and many APIs use milliseconds since the epoch (13 digits instead of 10). If a timestamp looks 1000× too big, it is in milliseconds — divide by 1000 to get seconds.
The year 2038 problem
Systems that store the timestamp in a signed 32-bit integer overflow on 19 January 2038. Modern systems use 64-bit timestamps, which push the limit hundreds of billions of years out.
Try it now — free, no signup
Use the timestamp converter in your browser. Then, when you need it at scale with an API key and higher limits, grab the full Eveses API.