Roof pitch chart explained

A roof pitch chart converts rise/run into approximate angle and an area multiplier. It is a quick reference while you plan materials—not a substitute for measuring your own roof.

How to read pitch, angle and multiplier

Pitch (e.g. 6/12) is rise over a 12-unit run. Angle is arctangent of rise/run, in degrees. Multiplier is √(1 + (rise/run)²). Multiply the building’s plan roof area by the multiplier to estimate surface area on that pitch.

Example: plan area 1,000 sq ft at 6/12 (multiplier ≈ 1.118) → about 1,118 sq ft of roof surface before waste, overlaps and features.

Common residential pitches

• 3/12–4/12 — lower slopes; check product limits for shingles
• 5/12–7/12 — very common on houses
• 8/12–12/12 — steeper; more surface area for the same footprint

Steeper pitches increase surface area and often labour difficulty. Material coverage charts still need waste factors for ridges, hips and starter courses.

Roofing squares

One roofing square is 100 square feet of roof surface. Estimators often talk in squares rather than raw square feet. Convert surface area ÷ 100, then add waste according to the product and roof complexity.

Our calculators can show square estimates from pitch and dimensions so you can sanity-check supplier quotes.

Using the chart with the tools

Look up a typical pitch, then verify with a real measurement when possible. Plug rise/run into the pitch tool and building length/width into the area tool. Compare the chart multiplier with the calculator output—they should agree for the same pitch.

Free roof pitch tools

Calculate pitch, angle, roof area, rafter length and material estimates from rise, run and building size.

Open the free calculators →

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