About Epoch Converter

What this site is

Epoch Converter does one job: it converts between Unix timestamps and human-readable dates, in any time zone, in both directions. It exists because the job comes up constantly for anyone who reads logs, debugs APIs or works with databases, and because many of the existing tools get the edge cases wrong — negative timestamps, daylight saving transitions, half-hour offsets, the seconds-versus-milliseconds guess.

Everything runs as JavaScript in your browser. There is no server-side component, no account, no upload. The page is a few files of plain HTML, CSS and JavaScript with no frameworks and no dependencies, which is why it loads instantly and keeps working if you save it and open it offline.

Design decisions

• Correctness before features. Time zone conversion is delegated entirely to the browser’s built-in Intl.DateTimeFormat and its IANA time zone database. No offsets are hand-computed anywhere in the code, because hand-computed offsets are wrong across DST boundaries and for historical dates.
• Explicit over silent. The unit detection is shown, not hidden, and can be overridden. Impossible and ambiguous local times are flagged. Invalid input produces a specific message rather than Invalid Date.
• Privacy by construction. Timestamps in logs often reveal more than people expect. Nothing you type is transmitted, because there is nothing to transmit it to — no server, no API, no endpoint.
• The converter needs no network. No web fonts, no icon libraries, no API to call. The conversion is a handful of local files plus your browser’s own time zone database, so it works with the connection pulled out.

Accuracy and corrections

The conversion logic is tested against a set of reference values including the epoch itself, 1000000000, -86400, the 2038 boundary at 2147483647, and round-trip conversions through zones with half-hour, quarter-hour and historical sub-minute offsets. If you find a case that converts incorrectly, please get in touch with the exact input, the time zone and what you expected — that is the most useful bug report possible for a tool like this.

How it is funded

The site is free to use. It may carry advertising to cover hosting costs. See the privacy policy for what that means for your data.

Start converting

• Timestamp to dateTurn an epoch number into a readable date in any time zone.
• Date to timestampGo the other way: calendar date and clock time to an epoch integer.
• Seconds vs millisecondsWhy your date landed in 1970 or in the year 55840, and how to fix it.