Roof pitch chart: angles, area multipliers, and how to measure your pitch
Full roof pitch chart from 1/12 to 12/12 with angles and area multipliers, why pitch raises roofing cost twice, and three ways to measure your own pitch — one without leaving the ground.
Roof pitch is written as rise over run: a 6/12 roof rises 6 inches for every 12 inches it runs. That one number sets your roof's angle, how much bigger the surface is than the footprint, and whether the crew needs harnesses. Here is the full chart and three ways to measure yours.
Roof pitch chart: rise, angle and area multiplier
Multiply your footprint by the multiplier to get actual roof surface. Multiplier = √(1 + (rise ÷ 12)²).
| Pitch | Angle | Area multiplier | Walkable? |
|---|---|---|---|
| 1/12 | 4.8° | 1.003 | Low-slope — needs membrane, not shingles |
| 2/12 | 9.5° | 1.014 | Low-slope — membrane or special underlayment |
| 3/12 | 14.0° | 1.031 | Yes — minimum for most shingles |
| 4/12 | 18.4° | 1.054 | Yes |
| 5/12 | 22.6° | 1.083 | Yes |
| 6/12 | 26.6° | 1.118 | Yes — the most common US pitch |
| 7/12 | 30.3° | 1.158 | Careful — many crews start staging here |
| 8/12 | 33.7° | 1.202 | No — harnesses and roof jacks |
| 9/12 | 36.9° | 1.250 | No |
| 10/12 | 39.8° | 1.302 | No — steep-roof labor premium |
| 11/12 | 42.5° | 1.357 | No |
| 12/12 | 45.0° | 1.414 | No — A-frames, Victorians, chalets |
Why pitch changes your roofing cost twice
- More surface. A 2,000 sq ft footprint is 2,236 sq ft of roof at 6/12 and 2,604 sq ft at 10/12 — 16% more shingles, underlayment and nails.
- Harder labor. Above roughly 7/12, crews slow down and rig fall protection. Most contractors add 10–25% to labor for steep roofs.
Quoting on the footprint alone — which some online calculators still do — under-prices a 6/12 roof by about 12%.
How to measure your roof pitch
1. From inside the attic (most accurate)
Hold a 12-inch level flat against the underside of a rafter, bubble centred, and measure straight down from the far end of the level to the rafter. That measurement in inches is your rise: 6 inches means 6/12.
2. On the roof or at the eave
Same method on top of the shingles, or against the fascia and the roof edge if you can reach it safely from a ladder. Measure over 12 inches of run.
3. Without leaving the ground
Stand back, photograph the gable end square-on, and use a phone level app or our roof pitch calculator, which visualises each pitch so you can match it by eye and returns the multiplier.
Calculate roof area with pitch: worked example
A 40 ft × 50 ft house has a 2,000 sq ft footprint. Rafters measure 8 inches of rise per foot, so the pitch is 8/12 and the multiplier is 1.202. Roof surface: 2,000 × 1.202 = 2,404 sq ft, or about 24 squares. Add 12% waste and you buy 27 squares of shingles. Our roof area calculator does this from your address.
Frequently asked questions
What is the most common roof pitch?
Between 4/12 and 8/12, with 6/12 the single most common on American single-family homes.
What is the minimum pitch for shingles?
2/12 with special underlayment; 4/12 for standard installation. Below 2/12 use a membrane roof.
How do I convert roof pitch to degrees?
Angle = arctan(rise ÷ 12). A 6/12 pitch is 26.6°; 12/12 is 45°.
Does a steeper roof cost more?
Yes: more surface area plus a labor premium above about 7/12. A 10/12 roof typically costs 25–35% more than the same footprint at 4/12.
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