What is a roofing square?

One roofing square equals 100 square feet. Shingles and other roofing materials are typically sold by the square.

How many bundles of shingles per square?

Standard three-tab shingles come 3 bundles per square. Architectural (dimensional) shingles may require 4 bundles per square — check the manufacturer's spec.

What pitch factor should I use?

Measure the rise (vertical inches) per 12 inches of horizontal run. A 6/12 pitch rises 6 inches for every 12 inches of run.

Why add waste percentage?

Cutting shingles around valleys, ridges, hips, and edges produces offcuts that cannot be reused. 10–15% is a standard allowance.

Does this include ridge cap or underlayment?

No — this calculates field shingles only. Ridge cap and underlayment are ordered separately based on the ridge length and total area.

Everyday

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Roofing Calculator - Squares Shingles Needed for Roof

Calculate roof squares, total square footage, and material needed with waste factor for any roof pitch.

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How to use this calculator

👉 Fill in the boxes below and your answer appears instantly — no maths needed, we do it all for you! 🎉

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In plain English — what does this do?

📊 A helper for daily life! Things like working out your age, how much to tip, what a sale price is, or how long until your birthday. Quick and easy answers for real life!

📌 Direct Answer & Summary

The Roofing Calculator estimates the total roof area and number of roofing squares needed for a gable roof. It accounts for roof pitch using a pitch factor multiplier and adds a user-defined waste percentage for cuts and overlaps. One roofing square equals 100 square feet.

Roof Length (ft)

Roof Width (ft)

Roof Pitch

Waste Percentage (%)

What is Roofing Calculator - Squares Shingles Needed for Roof?

How to use it

1️⃣ Enter the roof length and width (the footprint dimensions of the building).
2️⃣ Select the roof pitch from the dropdown (rise over 12-inch run).
3️⃣ Enter a waste percentage — typically 10% for simple roofs, 15% for complex ones.
4️⃣ Click Calculate to see total squares, square footage, and squares with waste.
5️⃣ Order at least the 'with waste' amount to ensure you have enough material.

Formula

Roof area = footprint area × pitch factor. Squares = roof area / 100. Pitch factors: 4/12→1.054, 6/12→1.118, 8/12→1.202, 10/12→1.302, 12/12→1.414. With waste: squares × (1 + waste%).

💡 See it in action — a real example

A 40 × 30 ft roof with a 6/12 pitch and 10% waste: footprint = 1200 sq ft. Roof area = 1200 × 1.118 = 1341.6 sq ft = 13.4 squares. With 10% waste = 14.8 squares (order 15).

❓ Common questions

What is a roofing square?: One roofing square equals 100 square feet. Shingles and other roofing materials are typically sold by the square.
How many bundles of shingles per square?: Standard three-tab shingles come 3 bundles per square. Architectural (dimensional) shingles may require 4 bundles per square — check the manufacturer's spec.
What pitch factor should I use?: Measure the rise (vertical inches) per 12 inches of horizontal run. A 6/12 pitch rises 6 inches for every 12 inches of run.
Why add waste percentage?: Cutting shingles around valleys, ridges, hips, and edges produces offcuts that cannot be reused. 10–15% is a standard allowance.
Does this include ridge cap or underlayment?: No — this calculates field shingles only. Ridge cap and underlayment are ordered separately based on the ridge length and total area.

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