What is a Unix timestamp?

A Unix timestamp (also called epoch time or POSIX time) is the number of seconds that have elapsed since midnight UTC on January 1, 1970 — the Unix epoch. It is a timezone-independent way to represent a moment in time as a single integer. For example, the timestamp 1700000000 represents November 14, 2023 at 22:13:20 UTC. Millisecond timestamps (common in JavaScript) are 1,000× larger than second-based ones.

Why does Unix time start on January 1, 1970?

The Unix epoch date was chosen somewhat arbitrarily when Unix was being developed in the late 1960s and early 1970s. The designers needed a recent, round date as a starting point. 1970-01-01 00:00:00 UTC was convenient and close enough to the present that timestamps for contemporary events would fit in a 32-bit integer. There was no deep technical reason for this specific date.

What is the Year 2038 problem?

32-bit signed integers can store a maximum value of 2,147,483,647. As a Unix timestamp, this value represents January 19, 2038 at 03:14:07 UTC. On systems that store timestamps as 32-bit signed integers, time will 'roll over' to negative values after this moment — causing dates to appear as December 1901. Most modern systems use 64-bit timestamps, which won't overflow for approximately 292 billion years.

How do I get the current Unix timestamp in code?

JavaScript: Math.floor(Date.now() / 1000) (seconds) or Date.now() (milliseconds). Python: import time; int(time.time()). Go: time.Now().Unix(). Bash: date +%s. SQL (PostgreSQL): EXTRACT(EPOCH FROM NOW())::int. Most languages have a built-in equivalent — the converter above also shows the live current value.

What is the difference between UTC and local time in timestamps?

Unix timestamps are always in UTC — they represent an absolute moment in time with no timezone attached. When you display a timestamp as a human-readable date, you choose whether to show it in UTC or a local timezone. The underlying integer is the same regardless of how it is displayed. This is why timestamps are the safest way to store and compare times across different timezones in software.

Encoding & Conversion

Unix Timestamp Converter

Convert between Unix timestamps and human-readable dates.

Current Unix Timestamp

1970-01-01T00:00:00.000Z

Timestamp → Date

Date → Timestamp

Unix timestamp — frequently asked questions

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