Question 1

How do I calculate roof pitch?

Accepted Answer

Roof pitch is the ratio of vertical rise to horizontal run, expressed as x:12 in the US. Measure the rise in inches over a 12-inch horizontal run — a rise of 6 inches gives a 6:12 pitch. To convert to degrees, use arctan(rise ÷ 12). A 6:12 pitch equals 26.57°.

Question 2

How do I convert roof pitch to degrees?

Accepted Answer

Use the formula: Degrees = arctan(rise ÷ 12) × (180 ÷ π). Common conversions: 4:12 = 18.4°, 6:12 = 26.6°, 8:12 = 33.7°, 9:12 = 36.9°, 12:12 = 45°. This calculator handles the conversion instantly from any input format.

Question 3

What is a pitch factor and how do I use it?

Accepted Answer

The pitch factor (also called roof multiplier) is √((rise/12)² + 1). Multiply your roof's flat footprint area by the pitch factor to get the true sloped surface area for ordering shingles, underlayment, or metal panels. A 6:12 pitch has a factor of 1.118 — a 1,000 sq ft footprint needs 1,118 sq ft of roofing material.

Question 4

What is the most common roof pitch for residential homes?

Accepted Answer

The most common US residential pitch is 6:12 (26.57°). It sheds water and snow well, works with most shingle types, allows usable attic space, and is safe to walk on without special equipment. Pitches from 4:12 to 9:12 are considered conventional and support all standard roofing materials.

Question 5

What roof pitch is too steep to walk on?

Accepted Answer

Roofs at 6:12 (26.6°) or less are generally safe to walk on without special equipment. At 7:12 (30°), caution is required. Above 8:12 (33.7°), safety harnesses and roof brackets are recommended. Above 12:12 (45°), specialized safety equipment is required.

Roof pitch calculator