How a labor unit works
Each line of the takeoff has a quantity. Each kind of work has a labor unit, in hours per unit. A fixture has hours per fixture. Conduit has hours per foot or per hundred feet. Quantity times labor unit gives the hours for the line.
- Take the quantity from the takeoff.
- Multiply by the labor unit to get labor hours.
- Multiply hours by the crew rate to get labor cost.
- Add the lines to get the total hours for the job.
Where labor units come from
- Your own job cost records. Hours spent, divided by units installed.
- Manuals published by trade associations.
- Manufacturer installation guidance for special equipment.
- The judgment of your field foremen.
Why you adjust them
A published labor unit assumes average conditions. Real jobs are not average. Adjust for the things that slow a crew down.
- Working height and lift access.
- Occupied buildings and limited work hours.
- Long carries from the truck to the work.
- Many small rooms against a few large ones.
- Weather and season.
- Overtime and stacked trades late in the schedule.
Why estimators use hours, not dollars
Wage rates change every year. Hours per unit change slowly. An estimate built on hours can be repriced with a new rate. It also gives the field a target: the foreman knows how many hours the bid carried.
Check the total
After you extend the lines, look at the total hours. Turn it into crew days. Ask your foreman if that crew could build the job in that time. This check catches a wrong labor unit faster than any formula.
Bidding and estimating · Updated 11 Nov 2026