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EVOA Toolbox

Unix Timestamp Converter

Convert Unix timestamps in seconds, milliseconds, microseconds or nanoseconds to dates (ISO 8601, RFC 2822, local, UTC) and back. Live clock and time zones.

Processed locally in your browser. Your text is not uploaded.

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What this tool does

Paste a Unix timestamp and see it as an ISO 8601 string, an RFC 2822 date, a UTC time and a local time in any IANA time zone, plus a relative description such as “3 hours ago”. Go the other way too: type a date and time and copy the matching seconds, milliseconds, microseconds and nanoseconds.

The unit is detected automatically from the size of the number: below 1e11 is treated as seconds, below 1e14 as milliseconds, below 1e17 as microseconds, and anything larger as nanoseconds. Today’s values are about 1.7e9, 1.7e12, 1.7e15 and 1.7e18 respectively. You can also force a unit. Integers are handled exactly with big-number arithmetic, so nanosecond timestamps do not lose precision.

A date without an offset, like 2024-03-10 02:30, is read in the time zone you select, and the tool tells you when that time does not exist or happens twice because of a daylight-saving change. Dates with Z or an explicit offset, and RFC 2822 text, are parsed as written. Everything runs locally.

How to use it

  1. 1Paste a timestamp. Leave the unit on Auto-detect, or choose seconds, milliseconds, microseconds or nanoseconds.
  2. 2Pick a time zone for the local time column. It defaults to your device’s zone.
  3. 3Read or copy the ISO, RFC 2822, UTC, local and relative values.
  4. 4To convert the other way, enter a date and time (or press Now) and copy the Unix values.

Supported formats

Input: integer or decimal Unix timestamps (negative values allowed), ISO 8601, RFC 2822 and “YYYY-MM-DD HH:mm:ss”. Output: seconds, milliseconds, microseconds, nanoseconds, ISO 8601, RFC 2822, UTC and local.

Privacy

This tool runs in your browser. The data you provide is processed on your device and is not sent to our servers.

Limitations

  • Auto-detect is a heuristic. A millisecond value before March 1973 is below 1e11 and will look like seconds. Select the unit manually for such values.
  • Dates are limited to the range JavaScript supports, roughly years -271821 to 275760.
  • Leap seconds are ignored, as in Unix time itself. Sub-millisecond digits are kept for display but local formatting is to the second.
  • Historical time zone rules come from your browser. Very old dates may use local mean time or approximations.

FAQ

What is a Unix timestamp?

The number of seconds since 1 January 1970 00:00:00 UTC, the Unix epoch. Many systems use milliseconds (JavaScript, Java) or nanoseconds (Go, some databases) instead.

How does auto-detect decide the unit?

By magnitude. Under 1e11 is seconds, under 1e14 milliseconds, under 1e17 microseconds, otherwise nanoseconds. If your value is ambiguous, pick the unit yourself.

Can I use negative timestamps?

Yes. Negative values are dates before 1970. For example -1 is 1969-12-31T23:59:59Z.

What if the local time does not exist?

When clocks jump forward, some wall-clock times never happen. The tool moves the time forward by the gap and shows a notice. When clocks go back, a time happens twice and the earlier occurrence is used.

Does anything leave my browser?

No. The conversion uses your browser’s built-in date and Intl features.

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