Time Tools · 5 min read

Unix Timestamp Converter — Epoch to Date and Back

Every computer counts time from January 1, 1970. Here's how to convert between that number and a date you can actually read.

What is a Unix timestamp?

A Unix timestamp (also called epoch time or POSIX time) is the number of seconds that have elapsed since January 1, 1970 at 00:00:00 UTC — a moment known as the "Unix epoch." Right now, that number is somewhere around 1.7 billion.

Developers use timestamps because they're timezone-independent, easy to store in databases, simple to compare (bigger number = later date), and take up very little space.

Seconds vs. milliseconds

Some systems (like JavaScript's Date.now()) return timestamps in milliseconds (13 digits), while traditional Unix time uses seconds (10 digits). ToolKnit's converter auto-detects which format you've entered and handles both correctly.

Two-way conversion

The tool works in both directions:

Live clock

The tool shows the current Unix timestamp updating in real time. This is useful for debugging APIs, checking log timestamps, or generating "right now" values for database queries.

Who uses this?

The Year 2038 problem

32-bit systems store Unix time as a signed integer that maxes out on January 19, 2038 at 03:14:07 UTC. After that, the counter overflows. Most modern systems have already moved to 64-bit timestamps, which won't overflow for another 292 billion years. ToolKnit uses JavaScript's 64-bit number type, so you're safe.

Try it now: Open Timestamp Converter — free, instant, no sign-up required.