Epoch Timestamp Converter

How it actually works

Both directions run on the platform's own date handling. A timestamp is read as seconds or milliseconds, turned into an instant, and rendered through Intl.DateTimeFormat for whichever zone you select, so the offset and the daylight-saving rule come from the browser's time zone database rather than from a fixed table written into this page.

Date to timestamp is the harder direction and it is now genuinely zone-aware. The tool solves for the instant whose wall clock in the named zone matches what you typed, iterating until the reading agrees, which is what makes a spring-forward boundary behave instead of drifting by an hour. Where the typed minute never existed because clocks jumped over it, or where it happens twice because clocks fell back, the result says so in words instead of returning a silently shifted number.

Ten zones are offered, from UTC and your own machine time to named IANA zones; a Now button stamps the current instant, and switching tabs carries a valid result across so you can see the same moment in both notations.

What that means for your results

Precision is at the millisecond: a 13-digit input is treated as milliseconds and a 10-digit input as seconds, and the format selector decides which is parsed, which removes the most common source of wrong answers when comparing a log line against a database column.

Because the offsets come from the browser database rather than a hard-coded assumption, a date six months in the future is evaluated against the daylight-saving rules currently installed on your system.

Where it falls short — honestly

JavaScript instants are signed milliseconds from the epoch, so values far outside ordinary use - centuries before 1970 or after 2200 - are out of scope, and the year field is deliberately bounded to keep nonsense out. A 10-digit value that is really milliseconds will still be read as seconds if the format selector says so; the tool cannot guess which you meant.

Named zones are only as good as the browser's zone database: an embedded or stripped-down engine may not know a zone, in which case the fallback is announced in the result line. Ambiguous wall-clock times during a fall-back resolve to the first occurrence.

A real end-to-end workflow

Use it when a log, an API payload or a database row hands you 1773097200 and you need to know when that was in the user's city: paste, pick the zone, read the date, then flip the tab and convert a deadline back to a timestamp for the query.

For durations between two instants rather than an absolute moment, Date Calculator counts the days, and Age Calculator does the same for a birth date. Timezone arithmetic across a whole year is better done with Unit Converter's time category, which converts between seconds, hours and days.