Does it support both seconds and milliseconds?
Yes. Unix Timestamp Converter automatically detects whether a numeric timestamp is in seconds or milliseconds and converts it accordingly.
Can I start from a local date instead?
Yes. Leave the timestamp field empty and pick a local date and time, and the tool converts it back into a Unix epoch value you can copy.
Does it show UTC and local time?
Yes. The converter shows the ISO string, UTC time, and your browser's local time together so the same instant is easy to read in every format.
Does it upload my data to a server?
No. Unix Timestamp Converter runs entirely in your browser with no backend, so every conversion is local and instant.
Is it free?
Yes. Unix Timestamp Converter is free to use with no account and no upload required.
Is my number in seconds or milliseconds?
Count the digits. A current Unix timestamp in seconds has 10 digits; in milliseconds it has 13. The converter uses the same heuristic, treating anything at or above 1,000,000,000,000 as milliseconds. It also reports which one it assumed, so check that row if the result looks wrong by a factor of a thousand.
Why is my converted time off by a few hours?
You are comparing a UTC output against a local expectation, or the reverse. The ISO and UTC rows are always in UTC. The Local row uses your browser's timezone, which is named in the Time zone field. A timestamp is a single instant; those rows are three views of it, not three different times.
How do I get the current timestamp?
There is no Now button. Either open the date picker, choose the current date and time, and convert, or paste a timestamp you already have. The absence of a Now button is worth knowing before you go looking for it.
Can I convert into a different timezone?
No. You get UTC and your own browser's timezone. Converting into a third zone, especially across a daylight saving boundary, needs a real timezone database and a zone picker, and this tool does not pretend to have one.
Does it handle leap seconds?
No, and nor does Unix time itself. Unix timestamps assume every day is exactly 86,400 seconds, so leap seconds are not represented at all. If you need true UTC with leap seconds, a Unix timestamp is the wrong format to be starting from.
Is anything sent to a server?
No. Everything is done with your browser's own Date and Intl objects. Timestamps out of production logs stay on your machine, which is the main reason to use this rather than the first result on a search engine.