Roof Shingle Calculator
Shingle bundles = roofing squares × bundles per square, plus waste. One square is 100 ft² of sloped roof, and most 3-tab and architectural shingles come 3 bundles to the square. A 2,400 ft² roof is 24 squares — 72 bundles exact, 80 with 10% waste. For the full material list, use the Roofing Calculator.
How it's calculated: Bundles = (roof surface area ÷ 100) × bundles per square, plus the waste allowance.
Result appears here
Fill in the fields and press Calculate.
Formula, calculation, assumptions and sources
Squares = Roof surface area (ft²) ÷ 100
Bundles = Squares × bundles per square
Run the calculation to see each step with your own numbers.
A roof with 2,400 ft² of surface area, 3 bundles/square, 10% waste.
Squares = 2,400 ÷ 100 = 24
Bundles = 24 × 3 = 72 exact
With 10%: order 80 bundles (≈ 26.4 squares)
- Roof surface area is the actual sloped area — not the building footprint.
- Standard asphalt shingles at 3 bundles/square unless you change it for your product.
- The waste allowance covers starter and hip/ridge — order dedicated starter strip and ridge cap separately if your manufacturer requires them.
- Underlayment, drip edge, flashing, nails and vents are not included.
- How many bundles in a square?
- Three, for standard 3-tab and most architectural asphalt shingles. Some premium/designer shingles are packaged 4 or even 5 to the square — the wrapper states it.
- Do I still need separate starter and ridge cap?
- Usually yes. This calculator's waste allowance covers the material used for them if you cut them from field shingles, but many manufacturers require purpose-made starter strip and hip/ridge caps for the warranty — buy those in addition.
- How many bundles of shingles do I need for 2,400 square feet?
- 72 bundles at 3 per square — 2,400 ÷ 100 = 24 squares — or about 80 with a 10% allowance for cuts, starter and ridge. Use the sloped roof area, not the footprint.
Roofing square
1 roofing square = 100 ft² of roof surface. Universal roofing-trade convention (NRCA).
Bundles per square
3 bundles per square for standard 3-tab and most architectural asphalt shingles. Asphalt Roofing Manufacturers Association (ARMA) / manufacturer packaging. Some heavy/designer shingles are 4–5 — adjust for your product.
Bundles per square — referenceWaste allowance
≈ 10% typical waste for a simple gable (cuts, starter, ridge); 12–15% for hips/valleys. NRCA / contractor practice. Editable.
About the Roof Shingle Calculator
The Roof Shingle Calculator converts a roof's sloped area into asphalt-shingle bundles and roofing squares, with editable allowances for waste and for starter and ridge courses. Get the area from the Roof Area Calculator first if you don't have it. It estimates field coverage — valley metal, flashing and underlayment are ordered separately.
What you enter
- Roof surface area — The sloped area, not the footprint. Use the Roof Area Calculator to get it from your footprint and pitch.
- Bundles per square — 3 for 3-tab and most architectural; 4–5 for heavy/designer shingles — check your product.
- Waste allowance — Default 10%. Adjust to your own allowance — the exact figure is always shown too.
What you get back
- Roofing squares — 1 square covers 100 ft² of roof.
- Shingle bundles — shown as the exact figure and, separately, a recommended figure with your waste allowance added.
The formula, a worked example, the assumptions behind it and the sources are shown in full below the calculator.
Related calculators
- Roof Area Calculator — Sloped surface area of a simple gable or hip roof from its footprint and pitch.
- Roof Pitch Calculator — Roof angle, slope factor and rise-in-12 pitch from a rise and run.
- Roof Replacement Cost Calculator — Estimated cost to replace a roof from its area, material and labour rates.
- Roofing Calculator — Overall roofing material estimate from roof area, pitch and material type.
Related articles
- How Roof Pitch Affects Roofing Materials — Pitch doesn't just change how much material you need — it can determine which roofing products are rated to work at all on a given slope.
- Asphalt Shingles vs Metal Roofing — Asphalt shingles and metal roofing differ in installation method, typical lifespan, weight and how they're estimated — here's a practical comparison.
Part of the Roofing calculators.