About TimeDuration

TimeDuration was built around the three places time arithmetic quietly goes wrong. First, the clock itself: subtracting 9:15 from 5:45 "by columns" produces borrowing errors, so everything here is converted to minutes since midnight and subtracted once. Second, midnight: a shift that ends at 6:30 AM after starting at 10:00 PM is a negative number to naive subtraction, so overnight handling is explicit — on, off, or locked on for the night-shift page — and the result always says when it was used. Third, decimal hours: 8:30 is 8.50, not 8.30, and the site converts and labels that everywhere instead of leaving the trap set.

The site covers the single duration (with break deduction and five output forms), a weekly time card that splits the week at 40 hours and labels — without overstating — the part above it, a duration adder, a two-way decimal converter, the full minutes-to-decimal chart, and three guides: calculating hours worked by hand, how overtime counting works, and how timesheet rounding works. Where rules vary — overtime, breaks, rounding — the pages say so and point to the employer and the jurisdiction as the authority; the arithmetic is the only thing claimed as exact.

All calculations run locally in your browser; see the privacy page for exactly what that means. TimeDuration is part of a small family of free tools. Pro features are planned at $9/month and are not yet on sale — everything on the site today is free.