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RoofCostLab

How We Calculate

Most roofing cost pages quote a range without saying where it came from. This page documents every input we use, so you can check our numbers or argue with them.

Labor

Labor starts from the U.S. Bureau of Labor Statistics Occupational Employment and Wage Statistics survey, May 2025 vintage, occupation code 47-2181 (Roofers). The national mean wage is $27.95/hour and the median is $26.65. We pull this from the raw national data file rather than a secondary summary.

A wage is not a billed rate. Roofing carries an unusually heavy labor burden, 50 to 70% against a 25 to 30% construction norm, because workers' compensation class code 5551 is the most expensive classification in the trades, running $15 to $45 per $100 of payroll. Adding burden and then overhead and profit gives the rate a homeowner is actually charged: 

$27.95 wage x 1.60 burden      = $44.72 fully-burdened cost
$44.72 / (1 - 0.375 OH&P)      = $71.55
national billed rate            ~ $78/hour

That $78 anchors a tier system running from $55/hour for ladder-level maintenance to $125/hour for emergency call-outs. Crew hours come from productivity benchmarks: asphalt installation runs 0.8 to 1.2 squares per hour per roofer, so a full tear-off and replacement is about 3.0 man-hours per square.

Materials

Material quantities are held per roofing square and scaled to your input. Prices come from 2026 published retail pricing. Where we have a verified in-stock retail price for a specific product, that price overrides our estimated range. About 39% of our material lines are verified this way.

Waste is applied on top: 12% for a standard asphalt roof, 15% for hip roofs and tile, 18% for slate and cedar where cuts waste more, and 8% for membrane systems that roll out in wide sheets.

Geometry

Roof area is the building footprint multiplied by the pitch multiplier, √(1 + (rise/12)²). A roofing square is 100 square feet. Asphalt shingles are three bundles per square. Every calculator on this site uses one shared, unit-tested implementation of this math, so a shingle count on one page cannot disagree with an estimate on another.

Where the 6/12 pitch multiplier comes from A right triangle. The horizontal side is the run, 12 units. The vertical side is the rise, 6 units. The sloping side is the rafter, which is the actual roof surface. By Pythagoras the rafter is the square root of 12 squared plus 6 squared, so every square foot of floor area carries 1.118 square feet of roof. Run: 12 Rise: 6 Rafter 26.6° Ridge Eave
A 6/12 pitch rises 6 inches for every 12 inches of run, which is 26.6 degrees. The rafter is 1.118 times the length of the run, so a 1,700 sq ft footprint at this pitch carries about 1,901 sq ft of roof. That multiplier is why roof area and floor area are never the same number.
One roofing square, and the 3 bundles that cover it A square grid ten cells wide and ten cells tall, each cell one square foot, making 100 square feet in total. That is one roofing square. Beside it are 3 stacked bundles of asphalt shingles, which is what it takes to cover that area. 10 ft 10 ft 1 square 100 sq ft 3 bundles
A roofing square is 100 square feet of roof surface, not one square foot. Roofers order and price in squares, and standard asphalt shingles run 3 bundles to the square. Converting early is what keeps the material order and the labor bid talking about the same roof.

Regional pricing

Selecting a state re-prices labor using BLS state-level roofer wages. Wages vary 1.7x across the fifty states, from Illinois at $37.33/hour down to Mississippi at $21.77, but billed rates compress relative to wages, because overhead and material costs travel less than payroll does. We therefore damp the wage multiplier toward 1 and clamp the result to 0.85–1.20 rather than applying the raw wage spread.

Permits

Where a permit is normally required we add the national band of $150 to $500, against an average of about $224. Maintenance and small repairs are usually exempt and carry no permit line.

What this cannot tell you

For those reasons every figure here is a planning range, not a quote. Use it to sanity-check the bids you receive and to understand what drives them. Get three written, itemised quotes before committing to work.

Corrections

If you are a roofing contractor and our numbers disagree with your market, we want to hear it. That is the fastest way this dataset improves. Email hello@roofcostlab.com with the job type, your region and your figure.