Is the end date included in the count?

The total days is end − start. Add 1 to count both endpoints inclusively (e.g. for project duration across both days).

How are months and years handled?

Calendar arithmetic: full years first, then full months, then the remaining days in the partial month. Different-length months are accounted for.

Yes — the totals are absolute, and the Direction card shows whether it's forward or backward in time.

Leap years are handled automatically by the JavaScript Date object — Feb 29 is a valid date in leap years.

No. Everything is computed in your browser.

Days, weeks, months & years between two dates — instant.

100% private — no uploads Calculator ToolsFree & unlimited Read tutorial

Watch a quick simulation of this tool in action — no file needed.

Follow these steps — everything happens instantly in your browser.

Everything you might want to know about date difference calculator.

Your exact age in years, months & days — plus a birthday countdown.

See one instant across the world's major timezones.

Three common percentage calculations — instant & private.

A real working calculator: functions, constants, memory & percent.