Worker days and crew duration per task, with the efficiency loss shown separately.
Programme, labour and cash flow. 5 questions answered below, each with the arithmetic behind it and the limits of what the tool decides. Open the Labour and Crew Productivity tool.
Labour is the largest line in most construction estimates and the one most often carried as a percentage. This tool converts measured quantities into worker days, using the productivity rates you set, so the labour line has the same traceability as the material lines beside it. The conversion is quantity divided by output per worker day, adjusted by the efficiency factor you enter. That efficiency factor is where the honesty lives: a gang working at scaffold height, in a heat wave or on a restricted site does not produce the textbook output, and pretending otherwise produces a programme that is optimistic and a labour cost that is short.
Six hundred square metres of blockwork at twelve square metres per worker day is fifty days of one person's work. With an efficiency factor of zero point eight five, which accounts for a site where the scaffold has to be moved, that becomes about fifty nine days. Against a programme allowance of twenty working days, the crew implied is three masons, which is the number that decides the labour cost and the sequence. If the rate were entered at eighteen square metres, the same wall would look like thirty three days, and the crew would be two, and the programme would slip.
By dividing each measured quantity by the output rate for that operation, then adjusting for the efficiency factor you set. Six hundred square metres of blockwork at twelve square metres per worker day is fifty days of work, and at an efficiency of zero point eight five it is fifty nine. The tool does that for each operation, sums by trade, and shows the crew size implied by the duration you want.
As a multiplier on the calculated days, applied explicitly so it can be seen and changed. Site conditions, access, weather and the learning curve all reduce output, and the factor is where that reduction lives. A factor of one assumes a textbook site, which few are. The value sits in the open rather than inside a rate, so a project manager can disagree with it specifically instead of arguing about the whole labour line.
Because a crew is booked for days, not for fractions of one. Rounding at the operation level rather than at the total is deliberate: three operations of two and a half days are three crews for three days each in practice, not seven and a half days that can be squeezed. Rounding also makes the labour line slightly conservative, which is the right direction for an estimate that has to be delivered against.
It is reported as missing and left out of the total, so the labour estimate shows where its own coverage stops. A default rate would produce a duration with nothing behind it, and labour durations feed directly into a programme that other trades are booked against. Where you do not know a rate, the honest move is to measure it on a similar job or to ask a foreman, and then to enter it.
No. It converts quantities into worker days and shows the crew implied. A programme needs logic: which operations precede which, how many crews can work at once, what the critical path is and where the float sits. That is a separate exercise with its own tool, and the labour hours from this page are one of its inputs rather than its output.