Unix Time Converter

About the Unix Time Converter

Unix time (also called Unix timestamp, POSIX time, or Epoch time) is a system for representing a point in time as a single integer — the number of seconds that have elapsed since 00:00:00 UTC on 1 January 1970, known as the Unix Epoch. It is the standard time representation used by operating systems, databases, programming languages, and APIs across the industry.

Seconds vs. milliseconds

The original Unix timestamp is measured in seconds. However, many modern systems — including JavaScript's Date.now(), Java's System.currentTimeMillis(), and most REST APIs returning timestamps — use milliseconds instead. This tool auto-detects which unit your input uses: values larger than 10 digits (greater than 10,000,000,000) are treated as milliseconds; smaller values are treated as seconds.

UTC vs. local time

A Unix timestamp is always UTC by definition — it has no timezone component. When converting a date/time to a timestamp, this tool lets you choose whether the date you entered is in your browser's local timezone or in UTC. This matters: entering 2024-01-01T00:00:00 as local time will produce a different timestamp than interpreting the same string as UTC, unless you happen to be in the UTC timezone.

Common use cases

• Decoding timestamps in API responses, log files, or database records
• Setting expiry times for JWT tokens, cookies, or cache headers
• Calculating a future Unix timestamp for a scheduled event
• Debugging time-zone-related bugs by comparing UTC vs. local representations
• Verifying that a timestamp stored as an integer represents the expected date

Quick reference

Privacy

This tool runs entirely in your browser. No timestamps or dates are sent to any server. Learn more about how Dev-Utilities handles privacy.