Every log line, JWT expiry and API response you'll ever debug carries one of these integers. Unix time counts seconds since midnight UTC, January 1, 1970 — one number, no timezone, no calendar, until a human needs to read it.
Seconds vs milliseconds: the digit tell
Current epoch seconds run 10 digits; JavaScript's Date.now() and many APIs use milliseconds — 13 digits. Feed either in: the converter counts digits, labels its assumption, and decodes accordingly. (A 10-digit value misread as ms lands in January 1970 — the classic "why is my date wrong by 55 years" bug.)
Why one integer beats a date string
Integers compare, sort and subtract: duration = t₂ − t₁, done. No DST edge cases, no "is 03/04 March or April," no timezone arithmetic — those complexities exist only at display time, which is why the converter shows both UTC (the canonical form) and your local rendering side by side.
2038, negative time, and leap seconds
Three famous corners: signed 32-bit counters overflow on January 19, 2038 (64-bit systems are fine for 292 billion years); negative timestamps validly encode pre-1970 dates; and leap seconds don't exist — Unix days are always exactly 86,400 seconds, absorbing Earth's rotational hiccups silently.
Around the tooling
The live ticker up top is today's epoch with one-click copy — handy for crafting test data. Duration math between two moments is the time duration calculator's job; date arithmetic ("90 days from now") belongs to the date calculator; and bytes-level encodings live in the binary translator.
All conversion local via the browser's date engine.