What is UNIX Time (Epoch Time)?
UNIX Time is a system for describing a point in time, defined as the number of seconds that have elapsed since 00:00:00 UTC on January 1, 1970 (the Epoch).
It is widely used as a standard format for handling dates and times in computer systems.
Why Use UNIX Time?
- Easy Comparison: Being a number, it’s simple to compare two timestamps or calculate the difference between them.
- Timezone Independent: UNIX Time itself is always based on UTC, allowing the same numeric value to be shared regardless of geographic location.
- Compact Data: It consumes less storage space compared to formatted strings (e.g.,
2026-01-14 12:00:00).
Seconds vs. Milliseconds
One of the most common mistakes in development is confusing seconds and milliseconds.
- Seconds (10 digits): Example:
1736823600. Frequently used in PHP, Python, and standard UNIX commands. - Milliseconds (13 digits): Example:
1736823600000. Common in JavaScript’sDate.now()and Java.
Checking which unit an API uses is crucial for accurate date calculation.
Handling Timezones and Offsets
While UNIX Time is always UTC, it must be converted to a local “Timezone” for human readability.
- UTC (Coordinated Universal Time): The primary time standard by which the world regulates clocks and time.
- JST (Japan Standard Time): 9 hours ahead of UTC (UTC+09:00).
The Year 2038 Problem
On older systems using 32-bit integers, UNIX Time will overflow when it reaches 2,147,483,647 (January 19, 2038, 03:14:07 UTC). Most modern 64-bit systems are immune to this issue.
Easy Conversion with DevToolKits
Calculating these manually is tedious and prone to error. Our tools provide instant, two-way conversion.
- UNIX Time Converter: Convert between UNIX Time (seconds/milliseconds) and formatted dates.
- Timezone Converter (UTC/JST): Supports date and time calculation across different timezones.
💡 Hint: Our tools also support the ISO 8601 format (
2026-01-14T12:00:00Z), making it convenient for verifying API specifications.