How this number is built
Four steps, all of them checkable on a pocket calculator.
1. The footprint becomes roof area
A roof is bigger than the ground it covers, because it sits at an angle. Divide the rise by 12, square it, add one, take the square root, then multiply your footprint by the result. A 6 in 12 roof works out at 1.118 times its footprint. A 12 in 12 is 1.414 times.
This is the step homeowners leave out, and it is a common reason a self-made estimate lands under the quote.
2. Roof area becomes squares
A square is 100 square feet of roof surface. Exactly 100. Contractors quote in squares and suppliers rate coverage by the square, though what comes off the truck is bundles. Three bundles cover a square for three-tab and for most architectural shingles. Heavy designer lines take more: four, five, and in two confirmed cases six.
3. The new roof is priced per square, installed
Published roofing rates are quoted as one figure per square with materials and labor together. We looked for a source that prices the two separately for the same product and could not find one, so this page does not invent the split. What is documented is the proportion: across three sources, labor runs 40 to 65% of the installed price on an asphalt job, and 60 to 70% on metal.
That proportion is useful for reading a quote. It is not enough to put a dollar figure on your materials line, and a page that did so would be showing you arithmetic dressed up as a source.
4. Taking the old roof off is its own line
Stripping the existing roof is quoted separately, and what is up there decides the price. One layer of asphalt runs $100 to $125 per square. Two layers is $125 to $175, not double, because the crew and the dumpster are already there. Wood shake is $150 to $200. Tile or slate is $200 to $400, because it is heavy and the disposal costs more.
Quotes that look surprisingly cheap are sometimes pricing a new layer over the old one. That is a different job with a shorter life, and it is worth asking which one you are being quoted.
Where waste went
Shingles get cut on every hip, valley and edge, and the offcuts are thrown away. Live roofing estimates apply about 15% waste on an ordinary roof, and a measurement report on a genuinely cut-up roof, 44 facets with 33 hips and 20 valleys, suggested 29%.
Whether waste appears on your bill depends on who wrote it. The published per-square rates this page uses already have it inside them, so it is not added again here. We show the material figure anyway, because it is what gets ordered, and because it is the number to check if a quote itemizes materials.
Where these rates come from
Every rate this page can produce, and the span the published sources actually cover. Gathered August 2026.
| Material | Most jobs | Full span of sources |
|---|
| What is up there now | Rate | Note |
|---|---|---|
| Asphalt, one layer | $100 – $125 | removal, haul away, dump fees, nail cleanup |
| Asphalt, two layers | $125 – $175 | a second layer adds about a third, not double |
| Wood shake | $150 – $200 | slower to strip |
| Tile or slate | $200 – $400 | heavy, and disposal costs more |
Where two columns differ above, the wider one is real. It usually means one publisher sits well outside the others, and we would rather show you that than quietly drop it. The full source list, with the publisher and the row each figure was read from, is on the methodology page.
The steep slope charge
Past 7 in 12 a roof stops being walkable for production work, and that is where the first paying line appears on an estimate: +14.6 to 18.8% on the install from 7 in 12 to 9 in 12, and +22.9 to 29.5% from 10 in 12 to 12 in 12.
That 7 in 12 is a pricing threshold, not a safety one. OSHA defines a steep roof as anything over 4 in 12, and fall protection is required at six feet up whatever the pitch. This page applies the charge to the install only. Estimators bill it a second time against the tear-off, and both figures come from 2021 estimates on regional price lists, so treat them as a floor.
What this calculator does not know about your roof
The decking underneath. If boards are soft or rotten they get replaced, and that is found on the day the old roof comes off, not before. Budget $75 to $150 a sheet if it happens.
Flashing around chimneys, skylights and walls, which is skilled work priced separately on most quotes.
How many stories up it is. The only priced example we could verify adds 8.3% to the install, and only on the squares actually above two stories, not the whole roof. One estimate on one regional price list is not a rate, so it is not in the arithmetic. Treat a tall house as the upper half of the range.
Where you live. Roofing labor is local, and the ranges here are national. The one regional instrument that prices an identical job across regions covers four of nine census regions, which is not enough to offer you a state to pick. Published roofer wages look like an answer and are not one: they run in the opposite direction to actual job cost in two of the metros we checked.
How cut up it is, for labor. The extra material on a complex roof is documented. The extra labor is not, in any source that survived checking.
Questions people ask before they call anyone
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How do I find my footprint if I do not know it?
Take the outside length and width of the house at ground level and multiply them. A garage under the same roof counts. A detached garage does not.
If the house is not a plain rectangle, split it into rectangles, work each one out and add them up. Most houses are two or three rectangles.
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How do I work out my pitch without getting on the roof?
From inside the attic, hold a level horizontally with one end touching the underside of a rafter. Mark 12 inches along the level, then measure straight up from that mark to the rafter. That measurement is your rise. Six inches means 6 in 12.
From the ground, a roof that looks easy to stand on is usually 6 in 12 or less, and one that looks alarming is 8 in 12 or more. Do not climb up to check. Falls are the roofing trade's leading cause of death, and the attic method costs you nothing.
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Why does the estimate not split materials from labor?
Because no source we could verify publishes both figures for the same product. The roofing trade quotes one installed price per square, and the materials-only numbers that do get published usually cover the field shingles alone, leaving out starter, ridge cap, underlayment, fasteners and waste.
We could have split the installed price using the 40 to 65% labor share and printed two confident lines. It would have looked more thorough and told you nothing we actually know.
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Why is the range so wide?
Because the honest answer is a range. The same roof quoted by three contractors in the same week routinely comes back hundreds of dollars per square apart, depending on crew size, backlog and whether they want the work.
The published rates for luxury asphalt and for concrete tile disagree far more than the rates for architectural shingles do, and the estimate widens to say so rather than picking a favorite.
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Should I shingle over the old roof to save money?
It is cheaper on the day. It also traps the condition of the old roof out of sight, adds weight, and shortens the life of the new shingles because they run hotter.
Most codes allow two layers and no more, so a second layer now usually means a full strip next time. If a quote is unusually low, it is worth asking which of the two jobs it is.
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Do you sell my address to a roofer?
No. There is no email field and no phone field on this site, and nothing you type is passed to a contractor.
The pricing arithmetic runs in your browser. When address lookup goes live, the address will go to our server for one step, to turn it into map coordinates through the US Census Bureau geocoder, and it will not be logged or stored.