Unix timestamp converter
Turn a Unix epoch into ISO-8601, UTC, and local time, or pick a date to get epoch seconds and milliseconds, all in your browser.
Seconds or milliseconds since 1970-01-01 UTC. Auto-detect picks by magnitude.
Interpreted in your local timezone, then converted to epoch time.
Now: 1781739417 s · 1781739417951 ms
Epoch in, human dates out
Paste a Unix timestamp and read it as ISO-8601, an RFC-style UTC string, your local time, and a relative phrase like “2 hours ago”, all at once. Auto-detect handles the common seconds-versus-milliseconds confusion, and a toggle lets you force either when a value is ambiguous. The reverse direction takes a date you pick and hands back the exact epoch seconds and milliseconds.
Native and private
Everything is computed with your browser's built-in Date and Intl APIs, no date library, no server, no account. That keeps the tool fast and fully offline-capable, and means timestamps from your logs, databases, or APIs stay on your machine.
Frequently asked questions
- Does this send my timestamp anywhere?
- No. The converter is plain JavaScript running in your browser using the built-in Date and Intl APIs. There is no upload and no network request; the values you enter never leave your device.
- What is a Unix timestamp?
- It is the number of seconds (or milliseconds) that have elapsed since 1970-01-01 00:00:00 UTC, known as the Unix epoch. It is timezone-independent, which makes it a compact, unambiguous way to store an instant in time.
- Seconds or milliseconds — how does auto-detect decide?
- By magnitude. A value of 1,000,000,000,000 (1e12) or larger is read as milliseconds; anything smaller is read as seconds. A 10-digit number is seconds, a 13-digit number is milliseconds. You can override this with the Seconds/Milliseconds toggle.
- Which timezone are the results in?
- ISO-8601 and the UTC line are always in UTC (Z). The Local line uses your device's timezone. The reverse picker interprets the date and time you choose in your local timezone before converting it back to epoch time.
- What is ISO-8601?
- An international standard date format, for example 2021-01-01T00:00:00.000Z. The trailing Z means UTC. It sorts lexicographically the same as it sorts chronologically, which is why it is a common choice for logs and APIs.