Unix timestamp converter

A Unix timestamp converter identifies an instant, not a timezone

Unix time counts forward and backward from January 1, 1970 at 00:00:00 UTC. The integer does not contain a timezone, a date format, a country, or a daylight-saving rule. Those appear only when software turns the instant into something a person can read. This converter shows UTC plus a selected display timezone so a local clock reading cannot be mistaken for information stored inside the timestamp. Choose the browser's local zone or enter an IANA name such as Europe/Stockholm. Zone names and historical offsets come from the browser's installed timezone data, so that human display is not a portable timezone database.

Negative values are valid and represent instants before the epoch. Zero is the epoch itself. The supported range is bounded by the browser's date representation rather than by a rule that rejects old dates. An out-of-range integer remains in the input with a specific error; it is never clipped to a different date that happens to fit.

Seconds and milliseconds cannot be guessed safely

Many Unix timestamps use seconds. JavaScript and several APIs use milliseconds. Logs and databases may use microseconds. A common converter guesses from the number of digits, which works on an ordinary current timestamp and fails on short test values, negative values, and dates far from today. The value 1000 can honestly mean sixteen minutes after the epoch, one second after it, or one millisecond after it. Digit count cannot decide.

Choose seconds, milliseconds, or microseconds explicitly. The receipt shows all three exact integer forms alongside the readable date. Browser dates carry millisecond precision, so a microsecond input keeps its exact integer while the human date makes the precision boundary visible instead of printing invented fractional time. If the timestamp came from structured data, the JSON formatter can expose the surrounding field without changing its number first.

Going from a date back to epoch requires an offset

The reverse direction accepts ISO 8601 with Z for UTC or a numeric offset such as 2026-08-15T14:30:00-04:00. That offset is not decoration. A local clock can skip an hour when daylight-saving time begins and repeat an hour when it ends. A bare 2026-11-01 01:30 can therefore identify two different instants in the same city. Guessing one silently would create a valid-looking but wrong timestamp.

Relative phrases such as “tomorrow morning,” locale-specific dates such as 08/09/26, and timezone abbreviations such as CST are not accepted. Their meaning depends on language, location, season, or convention. Add an explicit offset, then convert. When the deliverable is a calendar event rather than one integer, use the ICS file generator; it carries event fields instead of flattening the job to epoch arithmetic.

Useful when debugging tokens, logs, and APIs

Expiration and issued-at fields in web tokens are common timestamp sources. The JWT decoder identifies their signed payload values, while this page is the narrow place to inspect an arbitrary integer and its units. A timestamp conversion does not validate a token signature, prove that a server clock is correct, or tell you whether a session should still be accepted. It translates one representation of time.

Everything happens in this tab. Typing, paste, and a local text file enter the same integer or ISO parser. Values are not added to the URL, saved to browser storage, or sent to a time service. That boundary matters for production logs and token claims even when the value looks anonymous on its own. The local-processing guide shows how to inspect the network behavior directly.