Unix timestamp converter

What is a Unix timestamp?

A Unix timestamp (also called Unix time or epoch time) is the number of seconds elapsed since January 1, 1970 at 00:00:00 UTC — a moment known as the Unix epoch. It's a timezone-independent way to represent a single point in time as a plain integer.

Unix timestamps are used everywhere in computing: database records, log files, API responses, JWT tokens, file system metadata, and more. When you see a large number like 1700000000 in a codebase or API, it's almost always a Unix timestamp.

Seconds vs. milliseconds

Standard Unix timestamps are in seconds. JavaScript's Date.now() returns milliseconds — a value 1,000× larger. If a timestamp has 13 digits, it's likely in milliseconds; 10 digits means seconds. This tool works with second-precision timestamps; divide by 1,000 to convert milliseconds.

The Year 2038 problem

On 32-bit systems, Unix timestamps are stored as a signed 32-bit integer, which overflows on January 19, 2038 at 03:14:07 UTC — after which timestamps would wrap to a large negative number. Most modern systems use 64-bit integers, which won't overflow for approximately 292 billion years.

UTC vs. local time

Unix timestamps are always in UTC. The date displayed by this tool is converted to your local time zone, so the same timestamp may show a different date and time depending on where you are.