1:12–3:12
Low pitch
Often chosen for a lower profile or a broad, modern roof shape. Material selection matters more as water drains more slowly.
Free roofing tool
Roof pitch, made clear.
Calculate roof pitch, angle, slope and pitch factor instantly from rise and run.
Start with two measurements
Enter your rise and run
Use the same unit for both measurements. Inches are selected by default for common US roof measurements.
Vertical height from the lower edge to the roof peak.
Horizontal distance covered by the roof.
Try a common pitch
Your roof pitch
6:12
Angle
26.57°
roof angle
Slope
50%
rise ÷ run
Pitch factor
1.118
rafter multiplier
Rafter length
13.42 in
for this rise + run
The triangle is scaled for clarity; your measurements stay exact.
At a glance
What the result means
Roof pitch is a rise-over-run measurement written as X:12. The first number is how many units the roof rises for every 12 units of horizontal run.
The calculator also translates that relationship into the roof angle in degrees, slope as a percentage, and the pitch factor used to estimate the sloped length from a horizontal measurement.
For planning, use the same unit for rise and run. Actual roofing requirements can depend on the roofing material, manufacturer specifications, and local building codes.
Reference table
Roof pitch chart
Accurate conversions from common X:12 pitches.
| Pitch | Degrees | Slope % |
|---|---|---|
| 1:12 | 4.76° | 8.33% |
| 2:12 | 9.46° | 16.67% |
| 3:12 | 14.04° | 25% |
| 4:12 | 18.43° | 33.33% |
| 5:12 | 22.62° | 41.67% |
| 6:12 | 26.57° | 50% |
| 7:12 | 30.26° | 58.33% |
| 8:12 | 33.69° | 66.67% |
| 9:12 | 36.87° | 75% |
| 10:12 | 39.81° | 83.33% |
| 12:12 | 45° | 100% |
The formula
How to calculate roof pitch
Measure the vertical rise and horizontal run in the same unit, then use these formulas:
Pitch: (rise ÷ run) × 12
Angle: arctangent(rise ÷ run) × 180 ÷ π
Slope: (rise ÷ run) × 100
Pitch factor: √(1 + (rise ÷ run)²)
Rafter length: √(rise² + run²)
For example, a 6-inch rise over a 12-inch run is a 6:12 pitch, a 26.57° angle, and a 50% slope.
US roof pitches
Common roof pitch ranges
4:12–6:12
Medium pitch
A familiar residential range that balances a moderate roof angle with a practical, easy-to-read rise-over-run.
7:12 and up
Steep pitch
Creates a more pronounced roofline and more attic volume, with a larger sloped surface to account for.
These ranges are general descriptions, not design or construction advice. Confirm material requirements and local rules for your project.
Quick conversion
Pitch to degrees at a glance
A roof pitch is not itself an angle. Use the chart above, or enter your exact rise and run to convert roof pitch to degrees without rounding early.
Questions, answered
Roof pitch calculator FAQ
What is roof pitch?
Roof pitch describes how much a roof rises vertically for every 12 inches of horizontal run. A 6:12 roof rises 6 inches for each 12 inches of run.
How do you calculate roof pitch?
Divide the rise by the run, then multiply the result by 12. For example, 6 ÷ 12 × 12 = 6, so the roof pitch is 6:12.
What does a 6:12 roof pitch mean?
A 6:12 pitch means the roof rises 6 units for every 12 units of horizontal run. You can use inches, feet, or another consistent unit for both measurements.
What angle is a 6:12 roof pitch?
A 6:12 roof pitch has an angle of about 26.57 degrees, calculated with the inverse tangent of 6 ÷ 12.
Is roof pitch the same as roof slope?
They describe the same rise-over-run relationship, but they are usually written differently. Pitch is commonly expressed as X:12, while slope is often expressed as a percentage or ratio.
What is the most common roof pitch?
There is no single pitch used on every US home. Medium pitches such as 4:12 through 6:12 are common, but the right choice depends on the design, materials, climate, and local requirements.
How do I convert roof pitch to degrees?
Divide the pitch rise by 12, then calculate the inverse tangent and convert the result from radians to degrees. A 6:12 pitch is atan(6 ÷ 12), or about 26.57 degrees.
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