Question 1

What is a Unix timestamp?

Accepted Answer

A Unix timestamp is the number of seconds that have elapsed since January 1, 1970 at 00:00:00 UTC, known as the Unix epoch. It is a universal way to represent a point in time as a single integer, widely used in databases, APIs, log files, and programming languages.

Question 2

What is the difference between seconds and milliseconds?

Accepted Answer

Most Unix timestamps are in seconds. JavaScript's Date.now() returns milliseconds, which are 1000 times larger. If a timestamp looks like 13 digits (e.g. 1700000000000), it is in milliseconds. 10 digits (e.g. 1700000000) means seconds. This tool shows both so you can identify which format you have.

Question 3

Does Unix time account for time zones?

Accepted Answer

Unix timestamps are always in UTC. The human-readable display converts the UTC value to your local time zone using the browser's locale settings. The same timestamp represents a different local time depending on where you are.

Question 4

What is the maximum date a Unix timestamp can represent?

Accepted Answer

A 32-bit signed integer can represent timestamps up to January 19, 2038, a well-known issue called the Year 2038 problem. JavaScript uses 64-bit floating point numbers, so this tool supports timestamps well beyond 2038 without any limitation.

Question 5

Why would I need to convert a Unix timestamp?

Accepted Answer

Unix timestamps appear in API responses, database records, server logs, JWT tokens, and many other technical contexts. Converting them to a readable date helps with debugging, auditing, and verifying that a timestamp matches the expected date and time.

Unix Timestamp Converter

When to use this

Decode API responses

Debug JWT tokens

Check log entries