EstimatorKitFree roofing material take-off
Roofing calculator — the whole order, not just the squares
Enter a roof and get back everything that has to arrive on the truck: field material in squares and bundles, underlayment and ice barrier in rolls, starter and hip-and-ridge in bundles, drip edge and valley metal in 10 ft sticks, and nails by the pound. Six of those eight lines are driven by the five edge lengths you walk off round the building, not by the area, which is why a compact cut-up roof needs a bigger truck than a large plain one. Nothing is padded silently: the bare quantity and the quantity with your cutting allowance sit next to each other so the order can be laid beside a quote.
- 100% free
- No signup
- Eight material lines
- Waste set by roof shape
- Copies as a supplier list
Why 15%: hips and valleys cut into every course. The button sets the field below; type over it where your own offcut pile says otherwise.
Four squares to the roll, and the one that does not tear when the wind gets under it before the shingles go down.
Field material to order
21 squares
- Roof surface
- 1,789 sq ft
- Squares, bare
- 17.9
- Squares, plus 15%
- 20.6
- Bundles at three a square
- 62
The bare and padded figures sit side by side because only the bare one can be checked against a roofer’s quote — a bid is written in squares of roof, and the cutting allowance is the estimator’s own risk rather than part of the measurement.
Everything else the truck brings
| Synthetic underlayment400 sq ft on the roll, about 352 once the laps are taken off | 6 rolls |
| Ice barrier440 sq ft — 2 courses of 36 in up from the eave | 3 rolls |
| Starter course198 lf of eave and rake | 2 bundles |
| Hip and ridge cap82 lf of ridge and hip | 5 bundles |
| Drip edge10 ft sticks lapped 2 in, so 9.83 ft of each one is doing work | 21 sticks |
| Valley metal22 lf, lapped 6 in at each joint | 3 sticks |
| Roofing nails320 a square × 20.6 squares = 6,583 nails, at 140 to the pound | 47 lb |
Roll and stick sizes above are the common ones — drip edge is stocked in 10 ft lengths, a 36 in by 66.7 ft roll of self-adhered ice barrier is two squares, and typical coverage of a hip-and-ridge bundle which varies with product and exposure. Check them against the ticket before the order goes in; a yard that stocks a different roll length changes the count and not the coverage. The fastener line is the planning figure for a square of three-tab: 80 strips at four nails each, and it moves with shingle size — a laminate is 65 larger pieces a square and lands nearer 260.
Edge against area
302 linear feet of edge over 17.9 squares — 16.9 ft of edge per square. For scale, a plain gable over a 42 by 28 house at 6:12 runs about 14 and the same house hipped runs about 18, so this sits where a hipped or lightly broken-up roof sits, and the accessory lines are a real fraction of the order rather than an afterthought. 22 ft of that is valley, and every valley foot is two courses arriving from opposite directions and both getting cut.
How to take off a roof properly
One area figure, five edge figures, and one decision about waste.
Put in the surface, then stop thinking about area
Either enter the footprint with the pitch and let the multiplier do its work, or paste in a sloped surface you have already worked out and the pitch stops mattering to the quantity. This is the only area question the page asks. Everything after it is measured along edges, and that is deliberate: two roofs with identical square footage can differ by half a truckload once the trim is counted.
Walk the outline and write down five lengths
Eaves are the horizontal bottom edges, rakes the sloping ones up a gable end, ridges the horizontal tops, hips the outside corners running up from a plate, valleys the inside ones where two planes drain together. Total each of the five separately — both slopes of a gable are two eaves, and a valley between a wing and the main house is one line that costs two cut edges. A phone note and a walk round the building takes about four minutes and is worth more to the order than any refinement of the area figure.
Set the allowance from the shape, then keep both totals
The three preset buttons come from how the roof is cut rather than how big or how steep it is, and each fills the percentage box so you can type over it. What comes out is a bare figure and a padded one, side by side. Order against the padded one and check the roofer against the bare one — a bid is written in squares of actual roof, so a quote that quietly matches your padded number has an allowance of its own hidden inside it.
Technical specifications
| Area input | A ground footprint with a pitch, or a sloped surface entered directly — the second overrides the first |
|---|---|
| Cutting presets | 10% for a plain gable, 15% hipped, 20% cut up, each writing into an editable percentage field |
| Edge inputs | Five, totalled separately: eaves, rakes, ridges, hips and valleys |
| Underlayment | Synthetic and No. 15 felt at four squares a roll, No. 30 felt at two, with 12% taken off for laps before dividing |
| Ice barrier | 36 in rolls of 200 ft², run from the eave to 24 in inside the wall line, with the course count reported |
| Drip edge and valley | 10 ft sticks lapped 2 in and 6 in, so 9.83 and 9.5 ft of each stick lands on the roof |
| Fasteners | 320 nails a square at four per strip or 480 at six, converted at 140 nails to the pound |
| Data kept | None — the take-off is assembled in the tab and gone when it closes |
Frequently asked questions
What is on the truck besides the shingles?
Seven things, and six of them are measured in feet of edge rather than in area: underlayment over the whole deck, ice barrier along the eaves, a starter course at the eaves and up the rakes, hip-and-ridge cap along every ridge and hip, drip edge on every eave and rake, metal in the valleys, and nails. On a compact, heavily cut-up roof those seven can be a quarter of the material cost, and they are the lines a homeowner ordering from a square count discovers halfway through a Saturday.
Why does the form want five edge lengths instead of just the area?
Because area does not predict trim. A 20 squares roof laid out as one long rectangle might have 150 ft of edge; the same 20 squares as a house with two wings and a pair of dormers can carry 320 ft, and every accessory line doubles with it while the shingle count stays put. The panel under the results reports feet of edge per square for exactly this reason — it is the number that tells you whether the roof is cheap or expensive to cover, and it is invisible in a square count.
Is drip edge actually required, or is it a finish detail?
It is required under the IRC for asphalt shingle roofs at both eaves and rakes, and R905.2.8.5 sets how it is lapped and fastened. It is worth saying because drip edge is the line most often left out of a homeowner's order and the one most often argued about on a re-roof, where the old roof had none because it predates the requirement. It also does real work: without it the underlayment stops short of the gutter and water tracks back onto the fascia.
How many rolls of underlayment does a roof take?
About one roll per four squares for a synthetic, one per two for No. 30 felt — but not quite, because the stated area on the roll is flat area and the laps eat into it. This page takes roughly an eighth off the roll before dividing, which lands close to what actually gets used on a plain roof and slightly under on a cut-up one, where the offcut at every valley and hip is a full roll width. If your product prints its coverage after laps, the number on the wrapper already accounts for it and you are covered twice over.
How far up the roof does the ice barrier have to run?
From the eave edge to at least 24 inches inside the exterior wall line, which means the overhang and the wall thickness are spent before the code distance even starts. On a 12 inch overhang over a 2x6 wall that is roughly 44 inches of membrane measured up the slope, so a single 36 inch course does not reach and a second one is needed. Whether the requirement applies at all is a local determination based on the area's history of ice damming, and the building department holds that list.
My roofer quoted one price per square. How do I check it against this list?
Take the bare square figure, not the padded one, and divide the bid by it. That gives an all-in rate per square of real roof, which is the only form in which two bids can be laid beside each other. Then use the accessory counts here as a checklist against the written scope: a bid that includes ice barrier where a competing one does not is not more expensive, it is a different job, and the difference usually shows up in the number of rolls rather than in the price of a shingle.
What is left over at the end, and what should I hold on to?
A part bundle of field material, most of a box of nails, and whatever the last stick of drip edge did not need. Keep the field material and give the trim away: a stick of drip edge dents in the garage and is worth nothing in two years, while matching shingles are the difference between an invisible repair after a branch comes down and a patch you can spot from the street. The nails keep indefinitely if the box stays dry.
About taking off a roof by the whole order
Most roofing calculators answer the easy third of the question. Squares are the part that follows from geometry, and geometry is the part a computer is good at — but a roof arrives as eight separate products from three departments of a builders merchant, and seven of them are counted off the outline rather than the area. That is why an order built from a square count comes up short on a Friday afternoon: not because the squares were wrong, but because nobody counted the rakes. The panel that reports feet of edge per square exists to make that visible before the order goes in rather than after.
The cutting allowance is the other place these estimates part company with reality. A flat ten percent is the industry’s default and it is right for exactly one roof shape: the plain gable, where the only cut edges are the two rakes. Put hips on it and every course meets a diagonal, so every course gives up an offcut; add valleys, dormers and a turret and the pile in the driveway grows faster than the roof does. Steepness has nothing to do with it, which is the misconception this page is most often used to settle — a 12:12 gable wastes less material than a 4:12 with three dormers, even though the first is far harder to stand on. Take the outline seriously and the percentage looks after itself.
The area figure that feeds this page comes from the roof area calculator when the roof is more than one shape, or straight from a pitch and a footprint through the roof pitch calculator. Once the field quantity is settled, the shingle calculator breaks it down into pieces, courses and pallets, and the roof cost calculator puts your own rates against it. Walls under the same roof take off through the siding calculator, which handles the gable triangles the same way this page handles the rakes.
Where this take-off is assembled
Every number on this page is worked out by JavaScript running in the tab you are reading it in. Nothing you type — measurements, quantities, the prices your supplier quoted you — is uploaded, logged or kept, which is also why the calculators carry on working on a site with no signal.
The material list the Copy button builds is put together from the fields on this page and written straight to your clipboard. No supplier is contacted, no quote request is generated, and nothing about your roof reaches a merchant unless you paste it there yourself.