Calculate the precise duration between two dates and times. Get the breakdown in years/months/days, total seconds to total years, and business-day counts — all client-side.
Calendar breakdown advances year by year, then month by month, then days — matching how humans usually describe a duration ("3 years, 2 months, 17 days").
| Bucket | Days |
|---|
Weekdays = Mon–Fri. Weekends = Sat & Sun. The two endpoints are counted only if "inclusive" is on.
Calendar units are not fixed: a "month" is anywhere between 28 and 31 days, and a "year" can be 365 or 366 days. The calendar breakdown walks the calendar one boundary at a time so the months/days come out right. The total in each unit figures use fixed averages: 1 year = 365.25 days, 1 month = 30.4375 days. All math runs locally — no server roundtrips, no time-zone tricks beyond your browser's local zone.