Frequently asked questions
- Is my data uploaded to a server?
- No. Every operation runs inside your browser using JavaScript. Nothing you paste or type is sent to our servers, stored or logged. You can disconnect from the network after the page loads and the tool keeps working.
- Seconds or milliseconds?
- Unix time is defined in seconds, but JavaScript, Java and many APIs use milliseconds. This tells them apart by size - any timestamp with thirteen or more digits is milliseconds - and shows you which it used, so a value read the wrong way is obvious rather than silently landing in 1970.
- Which time zone is the result in?
- Both. The ISO and UTC lines are in UTC; the local line uses your browser's own time zone. A timestamp itself has no time zone - it is a count of seconds - so the zone only affects how it is displayed.
- What is the year 2038 problem?
- A signed 32-bit integer runs out of seconds on 19 January 2038. Anything storing timestamps in 32 bits will overflow then. This uses JavaScript numbers, which are good for dates far beyond that.
Related tools
Stuck on an error?
Every common JSON parse error is explained separately, with the cause and the fix: common JSON errors.
How your data is handled
Everything happens on your device. There is no upload, no storage and no logging, and only your interface preferences - theme, indentation, font size and word wrap - are kept between visits. Closing the tab clears the document.