CodeBeautifyUnix Timestamp Converter
Convert Unix timestamps online. Turn epoch time into a readable date, or a date into a Unix timestamp, in seconds or milliseconds, local time or UTC.
What is Unix time?
Unix time (also called epoch time or POSIX time) counts the number of seconds that have elapsed since January 1, 1970, 00:00:00 UTC, not counting leap seconds. It's used throughout computing — in databases, log files, APIs, and programming languages — because a single integer is simple to store, compare, and sort, and is unambiguous across time zones.
Seconds vs. milliseconds
The original Unix standard uses whole seconds, but many languages — including JavaScript's Date.now() — use milliseconds. As a rule of thumb: a 10-digit number is almost always seconds, and a 13-digit number is almost always milliseconds. Getting this wrong is one of the most common timestamp bugs, often producing a date in 1970 or the year 50000-plus.
Notable timestamps
| Timestamp (s) | Date (UTC) | Note |
|---|---|---|
0 | 1970-01-01T00:00:00Z | The Unix epoch |
946684800 | 2000-01-01T00:00:00Z | Y2K |
1234567890 | 2009-02-13T23:31:30Z | A famous "nice number" timestamp |
2147483647 | 2038-01-19T03:14:07Z | Max signed 32-bit value — the "Year 2038 problem" |
Frequently asked questions
How do I convert a Unix timestamp to a date?
Enter the timestamp, choose seconds or milliseconds, and the local time, UTC, ISO 8601, and relative time appear instantly.
How do I convert a date to a Unix timestamp?
Pick a date and time, choose whether to interpret it as local time or UTC, and the equivalent timestamp in seconds and milliseconds appears instantly.
Is a Unix timestamp in seconds or milliseconds?
The original Unix timestamp standard counts whole seconds since January 1, 1970 UTC. However, many programming languages and APIs (including JavaScript's Date.now()) use milliseconds instead. If your number has 10 digits it's very likely seconds; 13 digits usually means milliseconds. This tool lets you pick the unit explicitly.
What is the Year 2038 problem?
Systems that store Unix time as a signed 32-bit integer can only represent seconds up to 2,147,483,647, which corresponds to 03:14:07 UTC on January 19, 2038. After that instant, such systems overflow and can misinterpret the time as far in the past. Most modern systems now use 64-bit timestamps, which won't overflow for billions of years.
Can a Unix timestamp be negative?
Yes. Negative Unix timestamps represent dates before January 1, 1970, counting seconds backward from the epoch.