Convert Unix, ISO 8601, and RFC 2822 timestamps in one view

Why timestamp conversion keeps coming back

Different systems spell time differently. Kafka headers carry milliseconds, databases store microseconds, and frontends almost always want ISO 8601. Staring at an ambiguous number is an easy way to misread a deploy window or a billing event.

This page classifies the input the moment you paste it: 10 digits is seconds, 13 digits is milliseconds, 16 digits is microseconds. Human strings like `Tue, 14 Nov 2023 22:13:20 GMT` go through the JavaScript Date parser and expand into every other format.

What the tool does

• Numeric input → unit auto-detected (s/ms/μs) and converted to a Date
• ISO 8601 / RFC 2822 / loose date strings → parsed via Date
• Outputs: Unix s/ms/μs, ISO 8601 UTC, RFC 2822, local in the selected zone, weekday, relative time
• Time zone: browser-detected plus the 20 most common IANA zones

Gotchas worth remembering

1. `Date.now()` returns milliseconds while Python `time.time()` or Go `time.Now().Unix()` returns seconds. Systems that share timestamps must agree on a unit.

2. ISO strings without `Z` or an offset are parsed in the browser's local zone. Always include an offset if the value will cross systems.

3. Microseconds and nanoseconds lose precision in JavaScript Number. Use BigInt or keep them as strings when exact ordering matters.

FAQ

Q. Does it support future timestamps? Yes, anything inside the Date range (about ±100,000 years).

Q. What about negative timestamps before 1970-01-01? Supported — the ISO output shows the historical date with a minus sign.

Q. Is anything stored server-side? No, everything runs inside your browser.

Pairs well with

Jump to other JSON2Class utilities that naturally follow this one.