Unix Timestamp Converter

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. This moment is called the Unix Epoch. Timestamps provide a universal, timezone-independent way to represent a specific moment in time as a single number, making them the standard for storing and transmitting dates in computer systems.

For example, the timestamp 1700000000 represents November 14, 2023 at 22:13:20 UTC. Timestamps increase by one every second and are always in UTC, which eliminates timezone ambiguity. This simplicity is why timestamps are used in databases, APIs, log files, caching systems, and virtually every backend application.

Seconds vs. milliseconds

Most Unix systems and languages like Python, PHP, and Ruby use timestamps in seconds (a 10-digit number as of 2024). However, JavaScript, Java, and some databases use milliseconds (a 13-digit number). This tool detects the format automatically — if the number has 13 digits, it treats it as milliseconds. You can also toggle between the two formats manually.

How to use this tool

Enter a Unix timestamp (in seconds or milliseconds) to convert it to a human-readable date and time, or select a date and time to get the corresponding timestamp. The current timestamp is shown live for reference. The tool displays results in both UTC and your local timezone so you can see both representations.

Common timestamp uses

• Logging: Recording exact event times in application and server logs for debugging and auditing.
• Databases: Storing dates in a standardized, timezone-independent format that sorts correctly.
• APIs: Transmitting dates between systems reliably without timezone parsing ambiguity.
• Caching: Tracking cache creation and expiration times with simple numeric comparisons.
• Rate limiting: Enforcing request limits by comparing current time against stored timestamps.

Important Unix timestamp dates

• Unix Epoch (January 1, 1970): Timestamp 0 — the starting point for all Unix time.
• Y2K (January 1, 2000): Timestamp 946,684,800.
• Year 2038 problem (January 19, 2038): 32-bit signed timestamps overflow at 2,147,483,647. Systems using 32-bit time will wrap to negative numbers or crash.
• Billennium (September 9, 2001): Timestamp 1,000,000,000 — the first 10-digit timestamp.

The Year 2038 problem

Many older systems store timestamps as 32-bit signed integers, which can hold values up to 2,147,483,647. This maximum is reached on January 19, 2038 at 03:14:07 UTC. After that moment, 32-bit timestamps overflow and wrap to negative values, potentially representing dates in 1901. Modern 64-bit systems are not affected — a 64-bit timestamp will not overflow for another 292 billion years.

Is my data secure?

Yes. All conversion happens entirely in your browser using JavaScript's Date object. Your data never leaves your device. No timestamps or dates are logged, stored, or transmitted.

Frequently asked questions

Do Unix timestamps account for leap seconds?

No. Unix timestamps deliberately ignore leap seconds. Each day is treated as exactly 86,400 seconds. When a leap second occurs, the Unix timestamp either repeats a second or skips one, depending on the operating system. This simplification keeps timestamp arithmetic straightforward.

How do I get the current Unix timestamp in my code?

In JavaScript: Math.floor(Date.now() / 1000). In Python: import time; int(time.time()). In PHP: time(). In Bash: date +%s. All return the current time as a Unix timestamp in seconds.