ES-02Estimating

Man-Hours Calculator

What to calculate next

Tools commonly used alongside this calculation

Explanation

A man-hours calculator turns a quantity of work and a production rate into the total labor hours a job will take, how many work days that is for your crew, and what it costs. Man-hours are the backbone of a labor estimate: get the production rate right and load the hours with a wage, and the rest of the bid follows. This tool is vendor-neutral and works for any trade — enter your own rate, or one from a cost database like RSMeans.

How man-hours are calculated

Divide the quantity by the production rate to get the base labor hours, inflate them by the productivity factor for field conditions, then split across the crew to get calendar duration.

base man-hours = quantity ÷ production rate
effective man-hours = base man-hours ÷ (productivity % ÷ 100)
duration (days) = effective man-hours ÷ crew size ÷ hours per day
TermMeaning
quantityAmount of work (SF, LF, CY, each, …)
production rateUnits installed per labor-hour, per worker
productivity %Field efficiency — below 100% for real conditions
crew sizeWorkers sharing the hours (changes days, not total hours)

Man-hours and labor cost do not change with crew size — a bigger crew finishes the same labor in fewer days. To get the dollar figure, multiply the man-hours by your fully-burdened labor rate rather than the bare wage, so taxes, insurance, and benefits are covered.

Production rate vs labor unit

The same speed is written two ways. A production rate is units per hour (80 SF/hr); a labor unit is hours per unit (0.0125 hr/SF). They are reciprocals — RSMeans and most estimating databases publish the labor-unit form. This calculator accepts either. The values below are rough planning rates per worker; always confirm against your own crew’s history.

Task (example)Production rateLabor unit
Hang + finish drywall60–75 SF/hr~0.014 hr/SF
Paint roller, walls150–200 SF/hr~0.006 hr/SF
Lay CMU block~25 block/hr~0.04 hr/block
Install EMT conduit~15 LF/hr~0.067 hr/LF

Productivity factors

Published rates assume good conditions. Field work in practice runs at roughly 70–85% of ideal once setup, transitions, weather, access, and fatigue are counted. Set the productivity factor below 100% to inflate the hours accordingly.

ConditionTypical factor
Ideal / shop conditions95–100%
Normal field work80–90%
Difficult access / weather65–80%
Sustained overtime (50+ h/wk)70–85%

Sustained overtime erodes output: the 9th and 10th hours of a long day run about 85% of the first eight, and weeks of 50-hour schedules shed another 10–15%.

Notes and limitations

Production rates are local and crew-specific — the single biggest source of estimating error is using a generic rate instead of your own historical output. This tool gives the labor hours and cost; a complete bid still adds materials, equipment, overhead, and profit on top. Track actual hours against your estimates and feed them back into your rates over time.

Frequently asked questions