Unix time

Generally, 32-bit Unix time is a decimal representation of time that increases by one second from midnight (00:00) on January 1, 1970.
In binary it is expressed as follows.

Year 2038 problem

Simply because it was computed with 32 bits at the time, the maximum representable time is January 19, 2038 at 03:14:08 (UTC).
However, most computers today already use 64-bit computation, so no major problems are expected.
With 64-bit computation it can be used for about 300 billion years (until December 4, 292,277,026,596 at 15:30:08).

Leap second calculation

Leap seconds are ignored in Unix time.

Unix time (POSIX)

Current local time:

About This Calculator

Unix time (also called epoch time or POSIX time) is the number of seconds elapsed since 00:00:00 UTC on 1 January 1970, ignoring leap seconds. It is the standard timestamp format in databases, logs and APIs.

Enter a Unix timestamp to see the human-readable date, or enter a date to get its corresponding timestamp.

Unix time counts seconds since 1970-01-01 00:00:00 UTC and ignores leap seconds. At the start of 2025 it stood near 1,735,689,600 and it will pass 2,000,000,000 in May 2033. Because it is one integer it sorts correctly and is cheap to store, which is why databases, logs and APIs are built on it.

Key Formula:Unix time = seconds since 1970-01-01 00:00:00 UTC

Frequently Asked Questions

What is the Year 2038 problem?

Many older systems store Unix time in a signed 32-bit integer, which overflows on 19 January 2038. After that instant they would wrap to a negative number and misread the date. Most modern systems now use 64-bit integers.

Why is Unix time always in UTC?

Because it counts an absolute number of seconds with no timezone attached, which makes it unambiguous across the world. Timezones are applied only when displaying the value to a user.

Is Unix time always counted in seconds?

No. JavaScript, Java and many APIs use milliseconds, a thousand times larger. Mixing the two is a classic bug: a millisecond value read as seconds lands in the year 57,000.

Why does Unix time ignore leap seconds?

Leap seconds are inserted to keep civil time aligned with the Earth’s rotation, but Unix time pretends every day has exactly 86,400 seconds. That keeps arithmetic simple and means the clock can drift by a second or two from UTC over decades.

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Sources & last update

2026-10-19