Date to Unix timestamp Converter – Free, Online, Private

What is parsed

The value is passed to the Date constructor. An ISO string with Z is UTC. An ISO string with an offset such as +01:00 is that offset. A date-only string like 2026-10-16 is treated as UTC midnight by the ES5 ISO rule, which surprises people who expected local midnight. A string with a space instead of T may still parse in some browsers and fail in others. If the box reports that it could not parse the date, switch to the ISO form with a T and a Z. The output is the seconds since the epoch, truncating toward zero any fractional millisecond the Date cannot store, and the millisecond count.

Local wall time

A string without a zone, in the implementation-defined form, uses the browser's local zone. That means the same paste can produce two timestamps on two laptops. Put the zone in the string when the instant matters. The page also prints the UTC ISO form of whatever it parsed, so you can see whether local midnight shifted the day. This is the inverse of the Unix timestamp to date page, which starts from a number of seconds.

Worked example

2026-10-16T12:00:00Z is noon UTC on that day. The seconds value is a 10-digit number and the milliseconds value is that number times 1000. Pasting the seconds back into the timestamp page should show the same ISO string. A date in 1969 yields a negative timestamp, which is correct. Very far future dates run into the limits of the Date range and will fail the parse rather than wrap.

Not a calendar library

There is no business-day arithmetic and no timezone database beyond what the browser ships. Cron expressions are a schedule, not an instant; use the cron page for those. The parse is local to the tab.

Frequently asked questions