WhenMathEffort-to-Completion Calculator
Give any two of effort, daily capacity, and a date window, and solve for whichever one is missing, whether that's the completion date, the total effort a window can absorb, or the capacity a window requires.
Worked example
40 hours of effort at 8 hours a day needs 5 usable days to complete. Starting Monday, January 4, 2027, that lands on completion Saturday, January 9, under plain calendar days, with a partial final day still counting as one full usable day. Switch to a business-day calendar instead, and that same 5-day need pushes completion out to the following Monday, since weekends no longer count toward the usable days being consumed.
Common mistakes
- Using a flat daily capacity number that ignores holidays or blackout dates. See the Availability-Adjusted Completion Planner directly if those need to be accounted for.
- Assuming effort ramps up evenly from day one. This assumes a constant daily capacity throughout, not a gradual ramp-up period.
Limitations
This assumes constant daily capacity across the whole window. It does not model uneven effort, ramp-up periods, or partial-week availability that changes from one stretch of the project to another.
Frequently asked questions
- Does a partial final day round up?
- Yes, a fraction of a day's capacity still consumes one whole usable day when solving for a completion date, since a task cannot finish on a day that has not started yet.
- What does solving for capacity actually produce?
- It divides the total effort across the number of usable days between the start and end date, producing the daily capacity that would be needed to finish exactly on that end date.