Wood & Trim
Shingle Calculator
Estimate shingle bundles from sloped roof area or projected roof planes and pitch.
Enter your measurements
Results update as you type.
About this calculator
Enter the roof's sloped area directly, or enter projected plan areas with the roof pitch and let the calculator apply the slope factor. Add a waste percentage for hips, valleys and starter courses, then enter the coverage per bundle from your supplier. Bundles are the purchase unit; roofing squares are shown for reference only.
How to measure
- Measure the sloped surface of each roof plane, or its horizontal plan area with the rise per 12 units of run. Do not mix the two area bases.
- Projected-plane mode applies the entered pitch to every plane. Group planes of the same pitch, or use measured sloped areas for roofs with different pitches.
- Take bundle coverage from the actual product label; roofing squares do not imply a bundle size.
How to use this calculator
- Measure each roof plane — either its sloped area or its plan area.
- If you measured plan areas, enter the roof pitch.
- Add a waste allowance for hips, valleys and starter courses.
- Enter the bundle coverage from your supplier.
- Calculate for bundles to buy.
Formula
Sloped area of a projected plane = projected area × √(1 + (pitch ÷ 12)²)
Sloped planes are summed before waste
Order area = net sloped area × (1 + waste ÷ 100)
Bundles = ⌈order area ÷ coverage per bundle⌉
Roofing squares = order area ÷ 100 ft²
Assumptions
- Bundles are purchased whole.
- Sloped areas are surface areas, not plan areas, unless a pitch is supplied.
- Roofing squares are derived for reference and never determine bundle coverage.
Common mistakes
- Applying pitch to an area already measured on the slope.
- Assuming every product needs exactly three bundles per square.
- Rounding a fractional coverage value before calculating whole bundles.
Worked example
Try it: press “Load example” above the form.
90 m² of sloped roof with 10% waste is 99 m²; at 3 m² per bundle that is 33 bundles.
Limitations
Material quantity only. No roof access, fastening, wind rating, waterproofing, structural design or bundle coverage inferred from squares.
Frequently asked questions
Is a bundle always one third of a roofing square?
No. Three bundles per 100 ft² is an illustrative basis, entered exactly as 100/3. Product coverage varies, so read the bundle label before ordering.
Do I enter roof footprint or sloped area?
Choose the matching mode. A projected area requires a pitch factor, while a measured sloped area already includes slope. Do not apply the pitch factor twice.
What does the worked example show?
90 m² of sloped roof with 10% waste is 99 m²; at 3 m² per bundle that is 33 bundles.
Which assumptions should I check before using the result?
Material quantity only. No roof access, fastening, wind rating, waterproofing, structural design or bundle coverage inferred from squares.
Sources
Sources explain the methods and any named product presets. Check your product label where coverage, yield or density differs.
- Calculator.net: roofing geometry
Roof surface area and pitch context; bundle coverage must come from the actual product.
- IKO: how many shingles in a bundle
Three bundles per square (100 ft²) is the common default.
Calculation documentation · Updated 2026-11-08 · Version 1.6.4. Estimates are planning aids. Confirm quantities, coverage and prices with your supplier before purchasing. Found an error? Report it.
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