- Your outline, not an average From 129,591,852 mapped US building footprints.
- Two lines, both sourced Taking the old roof off, and putting the new one on.
- No email, no phone Nothing to sign up for, and no callback.
- Rates gathered August 2026 Each with the table and row it came from.
Which part of the house?
The roof calculator works now. The other three are being built.
- What does a new roof cost? Roof cost calculator. Your footprint and pitch, then the old roof off and the new roof on, priced as separate lines.
- How much gutter does my house need? Gutter cost calculator. Eave length worked out from the same outline. In progress
- What should new windows cost? Window replacement calculator. What people actually paid, next to what contractors quote. In progress
- How much siding will it take? Siding cost calculator. Wall area from your building's footprint and story count. In progress
How a roof estimate is actually built
Four things decide the number: the pitch, the count in squares, the installed rate, and what is already up there.
Your roof is bigger than your house
Seen from above, a house covers a certain patch of ground. The roof sits on top of that at an angle, so the surface you have to cover is always larger. How much larger depends on the pitch.
A 6 in 12 roof, a common residential pitch, has 11.8% more surface than the footprint underneath it. A steep 12 in 12 has 41.4% more. The multiplier is the square root of one plus the rise over the run, squared, so you can check both of those on a calculator in about ten seconds.
Leaving that step out is a common reason a homeowner's own estimate lands under the quote.
Roofers count in squares
A square is 100 square feet of roof surface. Exactly 100. It is a definition, not a rounding.
Contractors quote in squares and suppliers rate coverage by the square, though what comes off the truck is bundles. That is why an estimate never looks like the number you had in your head. A 1,353 square foot roof is 13.53 squares. For three-tab and most architectural shingles, three bundles cover a square. Heavy designer lines take four, five, and in two confirmed cases six.
Why we do not split materials from labor
The trade quotes one installed price per square, 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 site 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 is enough to read a quote with. 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.
Waste is real, and it is already in the price
Shingles get cut at an angle along every hip, valley and edge, and the offcuts are thrown away. Live roofing estimates apply about 15% waste on an ordinary roof. A measurement report on a genuinely cut-up roof, 44 facets with 33 hips and 20 valleys, suggested 29%.
You will not see waste as a line on your bill, because it is already inside the per-square price a contractor quotes. The example above shows the material figure anyway, because it is what gets ordered, and because it is the number to check if a quote itemizes materials.
Taking the old roof off is its own job
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. Tile or slate is $200 to $400, because it is heavy and costs more to dispose of.
On the example above that is about a sixth of the bill. If your roof already carries two layers, in most of the country the code will not let a third go on top.
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.
Why every website gives you a different national average
Five widely cited averages for a roof replacement run from $9,607 to $31,871, more than three times from end to end.
| Source | Average | What the figure covers |
|---|---|---|
| Angi | $9,607 | a national average across all roof sizes and materials |
| Fixr | $10,000 | 1,700 sq ft home, about 2,000 sq ft of roofing, asphalt |
| HomeGuide | $10,800 | asphalt shingles, size not stated |
| This Old House | $15,439 | 2,000 sq ft asphalt roof, from a survey of 1,000 homeowners |
| JLC Cost vs. Value 2025 | $31,871 | 30 squares, hip roof, stripped to bare wood, two skylights with custom flashing, vented ridge cap |
Some of that gap is scope. The last row is the only one from a construction industry cost study rather than a consumer site, and it prices a far larger and more complicated job than the others.
But scope does not explain all of it. Fixr and This Old House both price roughly 2,000 square feet of asphalt shingles, and they still differ by $5,439. Where the job is the same, what differs is the method behind the number. So averaging these five would give you a figure that describes no real roof at all. We price your roof from its own outline instead, and show you which line every dollar sits on.
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. It will go nowhere else. There is no email field and no phone field, and nothing is passed to a contractor.
Every rate here is dated. The rate table with its sources and the full formula are on the methodology page.
It is still an estimate. A real quote depends on the condition of the decking underneath, the flashing around chimneys and skylights, access for a dumpster, permit fees, how steep the roof is and how far off the ground it sits, and what your local crews are charging this season.