How to convert millisecond timestamps
- Paste a 13-digit timestamp such as
1700000000000into the converter. Milliseconds are preselected on this page. - Read the result in local time, UTC, ISO 8601 (with milliseconds) and relative form.
- To go the other way, pick a date and time zone in Date → timestamp; the Milliseconds row gives the value to use.
Seconds vs milliseconds
Unix time is traditionally counted in seconds, but many platforms count milliseconds: JavaScript's Date.now() and new Date().getTime(), Java's System.currentTimeMillis(), Kotlin, Elasticsearch, MongoDB dates, Kafka message timestamps and many JSON APIs. Mixing the two is one of the most common date bugs: a millisecond value treated as seconds points tens of thousands of years into the future, and a seconds value treated as milliseconds lands in January 1970.
Quick rule: if it has 13 digits, it is almost certainly milliseconds (until the year 2286). To convert, divide by 1,000 for seconds, or multiply seconds by 1,000. In JavaScript, new Date(ms) takes milliseconds directly, while new Date(seconds * 1000) is needed for seconds.
The live clock at the top shows the current milliseconds value. Everything runs in your browser.
FAQ
How do I convert milliseconds to seconds?
Divide by 1,000 and round down: Math.floor(ms / 1000). For example, 1700000000000 ms is 1700000000 seconds.
Does JavaScript use seconds or milliseconds?
Milliseconds. Date.now() and getTime() return milliseconds since 1970, and the Date constructor expects milliseconds.
What about microseconds and nanoseconds?
Switch the unit to microseconds (16 digits, used by Python and PostgreSQL) or nanoseconds (19 digits, used by Go and InfluxDB), or leave it on auto-detect.