Shingle Calculator

Calculate how many bundles of shingles you need from your roof area, plus ridge cap bundles, starter strip bundles and pounds of roofing nails, with waste included.

By CalcBuilt Editorial TeamUpdated September 9, 2026Formulas checked against manufacturer specs, see how we calculate.

Quick answer: To find how many shingles you need, divide the roof area by 100 to get squares, add waste, and multiply by 3 bundles per square. A 2,000 sq ft roof with 10% waste is 22 squares and needs 66 bundles, plus 2 bundles of ridge cap, 2 bundles of starter strip and about 46 lb of roofing nails.

Your measurements

Gable end: pitch is the rise over a 12 in run; the factor from that pitch turns footprint into roof area.

Roof surface areasq ftThe sloped surface, not the footprint. Use the roofing calculator to get it from ground measurements and pitch.Waste allowance%10% for a simple gable roof, 15 to 20% for hips, valleys and dormers.Bundles per square3 for 3-tab, GAF Timberline HDZ and Owens Corning Duration. Designer shingles such as Grand Sequoia and Camelot are 4 or 5. Check the wrapper.Ridge and hip lengthftTotal length of every ridge and hip that gets cap shingles. A ridge vent gets cap too, so do not subtract it.Eave and rake lengthftEvery eave and rake edge. Starter on the rakes is required for most enhanced wind warranties.Nails per square320 assumes 3-tab: 4 nails x 80 shingles per square, or 480 with the 6-nail high wind pattern. Architectural shingles run about 65 per square, so 260 or 390.

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Shingle bundles to buy66 bundlesAll results

Results

Shingle bundles to buy: 66 bundles; 22 squares x 3 bundles per square
Squares including waste: 22 squares; 2,000 sq ft is 20 squares before 10% waste
Ridge cap bundles: 2 bundles; At about 33 ft per bundle (Owens Corning ProEdge or caps cut from 3-tab); GAF Seal-A-Ridge covers 25 ft and Timbertex 20 ft
Starter strip bundles: 2 bundles; One bundle of starter shingles covers about 105 ft of eave and rake
Roofing nails: 46 lb; 6,400 nails; about 140 x 1-1/4 in roofing nails per lb

Shingle formula

Squares = Roof area (sq ft) / 100 x (1 + waste %)
Bundles = Squares x bundles per square, rounded up
Ridge cap bundles = Ridge and hip length / 33 ft per bundle
Nails = Squares (before waste) x nails per square  (about 140 nails per lb)

Worked example

A 2,600 sq ft hip roof with 15% waste: 2,600 / 100 = 26 squares, x 1.15 = 29.9 squares. At 3 bundles per square that is 89.7, so buy 90 bundles.

Accessories: 65 ft of ridge and hips / 33 = 1.97, so 2 bundles of ridge cap. 150 ft of eave and rake / 105 = 1.43, so 2 bundles of starter strip. Nails: 26 squares x 320 = 8,320 nails / 140 = 59.4 lb, so twelve 5 lb boxes.

Quick reference

Shingle bundles by roof area (3 bundles per square)
Roof area	Squares	Bundles, 10% waste	Bundles, 15% waste
1,000 sq ft	10	33	35
1,500 sq ft	15	50	52
2,000 sq ft	20	66	69
2,500 sq ft	25	83	87
3,000 sq ft	30	99	104
3,500 sq ft	35	116	121
4,000 sq ft	40	132	138

How to calculate shingles from roof area

Start with the sloped roof surface area. If you only have ground measurements, multiply the footprint (including overhangs) by the pitch factor first. Divide the area by 100 to get squares. Add 10 percent waste for a simple gable roof or 15 to 20 percent for hips and valleys. Then multiply by the bundles per square printed on the wrapper, usually 3.

Suppliers take back unopened bundles, so round up. Order every bundle from one lot number and check the wrappers at delivery; a second lot bought later shows as a color band across the slope. For 30 or more bundles, have a roofing supplier boom the load onto the roof. Two existing layers means a full tear-off (IRC R908.3), about 250 lb per square per layer for the dumpster.

Ridge cap, starter strip and nails

Every ridge and hip gets cap, including over a ridge vent. Coverage per bundle varies: Owens Corning ProEdge and caps cut from 3-tab run about 33 feet, GAF Seal-A-Ridge 25 and Timbertex 20. Starter goes on every eave and rake; GAF Pro-Start covers 120 feet a bundle and Owens Corning Starter Strip 105. Tabs cut off a 3-tab shingle also work, since the sealant stays at the eave.

Plan on 320 nails per square for 3-tab at 4 per shingle, about 260 for architectural. Six per shingle, 480 or 390 per square, is required for the 130 mph GAF and Owens Corning warranties and by many Florida and Gulf Coast jurisdictions. Use 1-1/4 inch 12 gauge nails on a bare deck and 1-3/4 inch over one old layer; R905.2.5 wants 3/4 inch into the sheathing or through it.

What this calculator leaves out

Drip edge on every eave and rake (R905.2.8.5). Ice barrier to 24 in inside the wall line where Table R301.2 lists ice dams (R905.1.2), plus every valley. Underlayment for the full deck, doubled from 2/12 to 4/12 (R905.1.1), one 10 square synthetic roll per 1,000 sq ft. Step flashing, pipe boots, ridge vent, 2 to 6 sheets of OSB for rot, tear-off labor, the dumpster and the permit.

Mistakes that cost money

Bundles from two lot numbers: the color bands shift at the break; check every wrapper at delivery and refuse a mixed load.
Ground delivery of 66 bundles: over 2 tons up a ladder; roofing suppliers boom bundles to the roof, typically $75 to $200 or free.
Four nails per shingle in a high-wind county: the 130 mph warranty needs six nails and the maker's starter strip; nail count goes up 50%.
One course of ice and water shield at the eave: R905.1.2 wants 24 in inside the wall line, which is two courses on most overhangs.
Architectural shingles upside down as starter: the sealant lands 5 in up the shingle and the first course blows off; use starter strip.
Assuming 33 ft of ridge per bundle: GAF Seal-A-Ridge covers 25 ft and Timbertex 20 ft; read the wrapper before ordering caps.

Key facts

One roofing square is 100 sq ft, and standard shingles are packed 3 bundles per square, about 33.3 sq ft per bundle.
A bundle of architectural shingles weighs 65 to 80 lb, so a 20 square roof adds roughly 2 tons to the truck.
Standard fastening is 4 nails per shingle; high wind areas and steep slopes use 6, raising nail count by 50%.
Roofing nails should be 12 gauge with a 3/8 in head, long enough to penetrate 3/4 in into the deck: 1-1/4 in for a single layer over sheathing.
A bundle of hip and ridge cap shingles covers about 33 linear ft, and a bundle of starter strip covers about 105 linear ft.

Frequently asked questions

How many bundles of shingles do I need for 2,000 square feet?

2,000 sq ft is 20 squares. With 10% waste that is 22 squares, or 66 bundles at 3 bundles per square.

How many square feet does one bundle of shingles cover?

About 33.3 sq ft for standard 3-tab and architectural shingles, since 3 bundles make one 100 sq ft square.

How many nails per bundle of shingles?

About 108 nails per bundle of 3-tab with 4 nails per shingle, or 160 with the 6-nail high wind pattern. That is roughly 320 or 480 nails per square. Architectural shingles are larger, about 22 per bundle, so 87 nails at 4 per shingle or 130 at 6.

Can I put new shingles over the old ones?

The IRC allows a second layer over one existing layer of asphalt shingles on a sound deck at 2/12 or steeper. It requires a full tear-off when two layers already exist (R908.3). Manufacturers limit warranties on a layover, you cannot inspect or replace rotten sheathing, and the nails need to be 1-3/4 in. Pros tear off.

Sources and references

Timberline HDZ shingles product page (GAF)
TruDefinition Duration shingles product page (Owens Corning)
Nail Application of Asphalt Strip Shingles technical bulletin (Asphalt Roofing Manufacturers Association)
Chapter 9 Roof Assemblies, 2021 IRC (ICC)

Next steps for this project

The usual order for a roofing & siding project. See all roofing & siding calculators.

Results are estimates based on standard formulas and typical product specifications. Confirm quantities with your supplier and local code before ordering.