Work out gantt duration instantly with clear inputs, formula shown and shareable results.
Converting a working-day duration into a calendar finish date requires stepping over weekends and public holidays. The calendar-to-working-day ratio of roughly 1.4 explains why a 45-day task takes over nine calendar weeks, which is the most common source of schedule surprise.
Finish date
Step forward from the start date, counting only working days, until the duration plus holidays is consumed
Ratio
Ratio = Calendar days elapsed / Working days consumed
They extend the calendar span but do not add effort, which is why they are counted as days to step over rather than extra work.
Convert the effort to elapsed working days at the actual availability before using this calculator, otherwise the finish date will be optimistic.