Unix Time Now

Unix time (also called epoch time, POSIX time, or Unix timestamp) is a system for tracking time as a running count of seconds. The counter starts at zero on January 1, 1970 at 00:00:00 UTC — a moment known as the Unix epoch. Right now, that counter is somewhere around 1.77 billion and climbing by one every second.

Unlike human date formats that vary by locale, language, and calendar system, a Unix timestamp is a single integer that means the same thing everywhere. It doesn't care about timezones, daylight saving time, or date formatting conventions. 1771287944 is unambiguous whether you're reading it in Tokyo, London, or New York.

This makes Unix time the standard for timestamps in databases, APIs, log files, JWT tokens, cookies, cron jobs, and virtually every system that needs to record when something happened. It's compact (4–8 bytes), trivially sortable, and makes duration calculations simple — just subtract one timestamp from another. To see unix time now, check the live counter at the top of this page. Use the epoch converter above to translate any timestamp to a human-readable date or vice versa.

In 1969, Ken Thompson and Dennis Ritchie at Bell Labs began building Unix on a PDP-7 minicomputer. The original system clock used a 32-bit integer counting 60ths of a second from an epoch of January 1, 1971. With 60-Hz ticks, a 32-bit counter would overflow in just over 2 years — not very useful.

By 1971, they switched to counting whole seconds, which extended the range to about 136 years. The epoch was shifted back to January 1, 1970 — a round number that was recent enough to keep values small but old enough that no relevant records would predate it. There was no grand technical reason; it was a practical choice that stuck.

The convention was codified in the POSIX standard (Section 4.16) and has been adopted by virtually every operating system, programming language, and database engine since. The epoch has never changed, and at this point, it never will. Unix timestamps are embedded in protocols you interact with daily — from DNS record TTLs to TLS certificate expiry dates and HTTP cache headers.

A frequent source of bugs: JavaScript's Date.now() returns milliseconds since the epoch (13 digits, e.g. 1771287944000), while most other languages and databases use seconds (10 digits, e.g. 1771287944).

Passing a seconds timestamp to a function expecting milliseconds gives you a date in January 1970. Passing milliseconds where seconds are expected gives you a date tens of thousands of years in the future. The quick diagnostic: count the digits. 10 digits means seconds, 13 means milliseconds.

To convert: multiply seconds by 1,000 to get milliseconds. Divide milliseconds by 1,000 (rounding down) to get seconds. The converter above auto-detects which format you've entered.