Unix Timestamp Converter

Unix Timestamp Converter

Current Unix timestamp:

Unix Timestamp → Human Readable Date

Please enter a valid Unix timestamp.

Date & Time → Unix Timestamp

Please select a valid date and time.

Unix Timestamp Converter – Epoch Time Made Simple

The Unix timestamp (also called Unix time, POSIX time, or epoch time) is the number of seconds that have elapsed since January 1, 1970, at 00:00:00 UTC — a moment known as the Unix epoch. Our converter instantly translates between Unix timestamps and human-readable dates in both directions, and displays your current timestamp live, updating every half second.

What Is Unix Time?

Unix time is a system for describing a point in time as a single integer, independent of time zones and locale. It was defined as part of the original Unix operating system in the early 1970s and remains the backbone of time handling across programming languages, databases, APIs, and operating systems. Every Linux/macOS system clock, every JavaScript Date.now() call, and every HTTP Last-Modified header uses this format under the hood.

Why Do Developers Use Unix Timestamps?

  • Time zone independence: A Unix timestamp in Tokyo is the same number as in New York. Time zone conversion happens only when displaying the value to a user.
  • Simple arithmetic: Subtracting two timestamps gives the elapsed duration in seconds. No need to handle month lengths, leap years, or DST when doing duration math.
  • Database storage: Storing an integer is more compact and faster to index than a datetime string. MySQL, PostgreSQL, and SQLite all support Unix timestamp columns.
  • API design: REST APIs commonly use epoch seconds in JSON responses for consistency across clients in different locales.

Seconds vs Milliseconds

Traditional Unix time uses seconds since the epoch (e.g., 1700000000). JavaScript's Date.now() returns milliseconds (e.g., 1700000000000). The converter auto-detects which you've entered: values larger than 10¹² are treated as milliseconds. You can toggle the live display to show either format using the checkbox above the live clock.

The Year 2038 Problem

Systems that store Unix time as a 32-bit signed integer will overflow on January 19, 2038, at 03:14:07 UTC — similar to the Y2K issue. Modern 64-bit systems are immune (they can store timestamps far into the future), but legacy embedded systems, older databases, and some 32-bit applications still face this risk.

Frequently Asked Questions

What is the Unix epoch?
The Unix epoch is January 1, 1970, 00:00:00 UTC. It is the reference point (timestamp = 0) from which all Unix timestamps are counted forward (positive values) or backward (negative values for dates before 1970).
How do I know if a timestamp is in seconds or milliseconds?
A 10-digit number (around 1,700,000,000) is in seconds. A 13-digit number (around 1,700,000,000,000) is in milliseconds. The converter automatically detects this based on magnitude.
Can I convert negative timestamps?
Yes. Negative Unix timestamps represent dates before January 1, 1970. For example, -86400 equals December 31, 1969, 00:00:00 UTC. Enter any negative number and the converter will display the correct date.
Does the converter account for my local time zone?
Yes. The tool shows both UTC and your local time zone. The UTC output is always the same regardless of where you are; the local output reflects your browser's configured time zone.
Is the live timestamp accurate?
The live timestamp is derived from your device's system clock via JavaScript's Date.now(), refreshing every 500 ms. It is as accurate as your device's clock, which for most modern systems is synchronized via NTP to within milliseconds of UTC.