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.

Every input, with its source

Labor

Labor starts from the U.S. Bureau of Labor Statistics Occupational Employment and Wage Statistics survey, May 2025, occupation code 47-2181 (Roofers). The national mean wage is $27.95/hour and the median is $26.65. Both are on the BLS OEWS page for roofers, which also lists the state figures our regional pricing uses.

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 among the most expensive classifications in the trades. Adding burden and then overhead and profit gives the rate a homeowner is actually charged. At the middle of both ranges:

$27.95 wage x 1.60 burden     = $44.72 fully-burdened cost
$44.72 / (1 - 0.375 OH&P)     = $71.55 billed
at the top (1.70, 0.40)       = $79.19 billed
anchor used                   = $78.00

The middle of the assumptions gives $71.55 and the top gives $79.19. We anchor standard roofing labor at $78, near the top of that span. Using the midpoint instead would lower every labor line on the site by about 8%, and if your local contractors bill below our figures, that is the first number to argue with.

The $78 anchor moves by job type: $65/hour for gutter work, $85 for leak and flashing work where a mistake means water inside, $92 for specialty systems such as metal, tile and skylights, $105 for slate and cedar, and $125 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 person-hours per square.

Materials

Material quantities are held for each job's default size and scaled to your input. Prices come from 2026 published retail pricing. Where we have a verified in-stock retail listing for a specific product, that price is used and the row links to it; 73 of 201 lines are verified this way.

Where a published range looked wrong, we checked it against retail listings and against the published cost guides at HomeGuide, Angi, This Old House and Homewyse. Nothing on this site is copied from those guides, but they were used to sanity-check material bands, and saying so is part of showing the work.

Quantities are what a roofer orders, not what the roof measures. Anything sold whole (bundles, rolls, sticks, boxes, the skylight itself) is rounded up to a whole unit, and the waste allowance is applied only to materials that get cut to fit. A skylight, a vent or a dumpster carries no waste allowance, because none of it ends up as offcuts.

What changed on October 23, 2026

Every material line was checked against the job it prices. The review found and fixed errors that had been in the dataset since launch. The common pattern was a product sold in a pack, such as a 50-foot roll of flashing or a 10-foot stick of drip edge, whose quantity had been entered in the job's own units:

• A 200 sq ft porch roof was priced with 1,680 feet of flashing, a 20-foot valley repair with 42 bundles of shingles, and a decking repair with 2,240 feet of flashing.
• Full shingle roofs carried ten boxes of nails per 1,000 sq ft, about ten times what the job uses.
• Several lines priced an installed rate as if it were the material: drip edge, flashing repair, chimney membrane.
• Labor hours on slate, cedar, porch roofs, decking repair and underlayment replacement were below what the work takes, and the step-by-step timelines did not add up to the hours priced. Both now agree.
• Fasteners and metals were matched to the job: ring-shank nails for shakes and sheathing, galvanized steel rather than aluminum against masonry, a 24-inch liner for open valleys.

An automated check now multiplies every pack size out against the job and fails the build if the result cannot fit, so this class of error cannot return unnoticed.

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.

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 move only 60% of the way toward the state's wage ratio and hold the result between 0.85 and 1.20, rather than applying the raw wage spread. Materials are priced nationally.

Permits and tear-off

Where a permit is normally required we add the national band of $150 to $500; published permit data puts the average at about $224. Maintenance and small repairs are usually exempt and carry no permit line. On a full replacement, tear-off and disposal of the old roof are priced per square of roof, with a second layer at about half again the first.

What this cannot tell you

• The condition of your roof deck, which is invisible until tear-off and commonly needs some replacement on an older roof.
• Access constraints. A steep lot, tight setbacks or no dumpster space all add hours.
• A steep-slope charge. Most contractors add one once a roof is too steep to walk, and published figures for it vary too widely to model honestly; ask for it as its own line.
• Local disposal fees, which vary widely by county.
• Your specific contractor's overhead, backlog and pricing.

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, itemized 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.