Production is where labor estimates are won or lost
Material quantities come off the plans and material prices come from suppliers. Labor is different. The number of hours a job takes depends on how much a crew can install in a day, and that’s where most subcontractor estimates carry the most risk. Use a rate that’s 10% too optimistic and a job with a healthy margin can finish at break-even.
This estimator makes the production assumptions visible. Every activity shows the quantity, the rate per crew-day, the crew and the result, and the job conditions that change the rate are listed as separate factors, so you and your project manager can argue about the right thing.
How the estimator works
- Add activities from the library or your own. The library holds typical rates for sitework, concrete, masonry, steel, framing, drywall and ceilings, finishes, roofing, plumbing, HVAC, fire protection, electrical and demolition, each with a typical crew and a low-to-high range. Custom activities take any unit.
- Enter quantities from your takeoff, the crew size, and how many crews will work the activity at the same time.
- Set the job conditions. Access and congestion, weather, working height, crew experience, hours and shifts, and repetition each have a factor. They multiply together into one condition factor.
- Read the results. For each activity:
- Adjusted rate = typical rate × condition factor × (hours per day ÷ 8)
- Crew-days = quantity ÷ adjusted rate
- Duration = crew-days ÷ crews, rounded up to the half day
- Labor hours = crew-days × crew size × hours per day
- Equipment days = crew-days × equipment units per crew
The schedule places activities back to back to give a total duration in working days and weeks. Real jobs overlap trades, so treat it as the longest the work should take with the crews you’ve planned.
A worked example
A drywall and ceilings contractor is pricing a three-floor office interior buildout of 42,000 square feet. Crews work 8-hour days, 5 days a week, at a blended labor cost of $68 an hour. Most of the work is from ladders and rolling scaffolds, a 0.92 factor; everything else is typical.
| Activity | Quantity | Typical rate | Adjusted | Crews | Crew-days | Days |
|---|---|---|---|---|---|---|
| Metal stud partitions | 18,400 SF wall | 1,000 | 920 | 2 | 20.00 | 10 |
| Door frames, doors, hardware | 42 openings | 8 | 7.36 | 1 | 5.71 | 6 |
| Batt insulation | 9,200 SF | 2,800 | 2,576 | 1 | 3.57 | 4 |
| Hang gypsum board | 36,800 SF | 2,400 | 2,208 | 2 | 16.67 | 8.5 |
| Tape and finish, level 4 | 36,800 SF | 1,600 | 1,472 | 2 | 25.00 | 12.5 |
| Acoustical ceilings | 12,500 SF | 1,000 | 920 | 1 | 13.59 | 14 |
| Total | 84.54 | 55 |
The job needs 84.54 crew-days, 1,352.5 labor hours and about $91,970 of labor, over 55 working days (11 weeks) if the activities run in sequence. The ceiling crew needs a scissor lift for 13.59 days.
At typical conditions, the same work takes 77.77 crew-days. The ladder-and-scaffold factor adds 6.8 crew-days, roughly 108 hours or $7,360 of labor. That’s the number to put in front of the GC if the building turns out to have 14-foot ceilings instead of 10.
Putting a third crew on tape and finish cuts that activity from 12.5 to 8.5 days without changing the crew-days or the cost. Crews change the schedule; production changes the price.
Getting better production numbers
- Track your own. Record installed quantity and crew hours by activity on a few jobs. Two or three data points beat any library.
- Separate the easy and hard areas. Price a corridor of long straight walls apart from a lab full of penetrations, each with its own rate.
- Be careful with overtime. Extended overtime lowers productivity after a couple of weeks; use the hours and shifts factor.
- Check the crew mix. A rate is for the typical crew listed. A crew with fewer skilled workers produces less.
- Include what the rate doesn’t. Layout, cleanup, material handling and punch list are often carried separately.
Related tools
Production gives you hours; the labor burden calculator gives you the true cost of each hour. Durations feed jobsite overhead in the general conditions estimator, and when conditions change mid-job, price the lost production with the change order pricing calculator.