Labour Days and Crew Calculator
Man-days, crew size and labour cost from output rates.
Inputs
Result
Formula
| Man-days | quantity ÷ output per man-day |
| Crew | man-days ÷ (duration × attendance) |
| Rounding | round up to a whole person |
| Actual duration | man-days ÷ (crew × attendance) |
| Cost | man-days × rate |
| Unit labour | man-days ÷ quantity |
100 m² at 8 m² per man-day over 10 days at 95% attendance and 350 per man-day: 12.5 man-days, 1.32 people rounded to 2, an actual 6.6 days and 4375 in labour.
FAQ
Are output and time standards reciprocals?
Yes. The output rate says how much one man-day completes, in m² per man-day; the time standard says how many man-days a unit needs, in man-days per m². 8 m² per man-day is 0.125 man-days per m². Quotes read better in time standards, crew planning in output rates — take the reciprocal.
Why does 1.32 people become a crew of 2?
Because people do not split. Rounding up cuts the duration to 6.6 days but leaves idle time; one person alone takes 13.2 days and misses the date. In practice you crew one and add help on the critical days, or borrow from an adjacent trade. The decision compares the deadline against the cost of idle time, not the arithmetic.
Is man-days times rate an accurate labour cost?
Only as a baseline. Real settlement works three ways: daywork against attendance, piecework against measured quantity, and supply-and-fix. Piecework rates already carry the efficiency risk and typically run 15-30% above the computed man-day cost. Estimate the floor from standards, quote from piecework rates, and the gap is your margin.
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Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.