Pitch ratio
6/12
Standard rise / run format used by roofers and estimators.
LumioForge Free Roofing Tool
Roof Pitch Calculator
Use this roof pitch calculator to convert rise and run into a roof slope ratio, pitch to degrees, percent grade, and roof pitch chart multiplier. It is built for roofing estimators, sales reps, office staff, and homeowners who need clear roof slope numbers fast.
Rise / run inputPitch to degreesPercent gradeCopy-ready results
Roof slope calculator
Enter the rise and run from a framing square, drone report, inspection note, or measurement sketch. The calculator updates instantly.
Rise
Run
What to enter
Typical roofing pitch is measured in inches of rise for every 12 inches of run, but this calculator also works with other run values.
Roof pitch results
Use the ratio, angle, and slope factor in takeoffs, estimating templates, and roof area calculations.
Pitch ratio
6/12
26.57 deg roof angle with a 1.118 multiplier.
Percent grade50.00%
Pitch multiplier1.118
Rise per 126.00/12
Copy the current roof pitch calculator output into an estimate, inspection note, or homeowner email.
Pitch to degrees
26.57 deg
Useful for plans, design coordination, and pitch chart conversions.
Slope factor
1.118
Multiply footprint area by this number to estimate sloped roof area.
How to use this tool
- 1
Measure how many inches the roof rises over a known horizontal run. Most residential roof pitch measurements use a 12-inch run.
- 2
Enter the rise and run values exactly as measured. The roof pitch calculator converts them into ratio, degrees, percent grade, and slope factor.
- 3
Use the pitch multiplier in the related roof area calculator when you need to turn footprint measurements into actual roof surface area.
How the math works
Pitch ratio and percent grade
Pitch ratio is written as rise over run, such as 6/12. Percent grade is the same ratio expressed as a percentage: rise / run x 100.
Pitch to degrees
Roof angle in degrees is calculated with arctangent(rise / run). That gives the exact angle for layout, estimating, and converting pitch to degrees.
Slope factor / pitch multiplier
The roof pitch chart multiplier comes from the Pythagorean theorem: sqrt(rise^2 + run^2) / run. Use that factor when you need to turn a flat footprint into sloped roof area.
Common roof pitch chart
| Pitch | Degrees | Percent | Multiplier |
|---|---|---|---|
| 3/12 | 14.04 deg | 25.0% | 1.031 |
| 4/12 | 18.43 deg | 33.3% | 1.054 |
| 5/12 | 22.62 deg | 41.7% | 1.083 |
| 6/12 | 26.57 deg | 50.0% | 1.118 |
| 8/12 | 33.69 deg | 66.7% | 1.202 |
| 10/12 | 39.81 deg | 83.3% | 1.302 |
| 12/12 | 45.00 deg | 100.0% | 1.414 |
FAQ
How does a roof pitch calculator convert pitch to degrees?
The calculator uses the arctangent of rise divided by run. A 6/12 roof pitch means the roof rises 6 inches for every 12 inches of horizontal run, so the angle is `atan(6 / 12)`, or about 26.57 degrees.
What is percent grade on a roof slope calculator?
Percent grade is rise divided by run multiplied by 100. A 6/12 pitch equals 50% grade because 6 divided by 12 is 0.5.
What is the pitch multiplier used for?
The pitch multiplier, sometimes called the roof slope factor, converts flat footprint area into actual sloped roof area. Contractors use it to move from building footprint to roof surface measurements.
Is a 12/12 roof pitch the same as 45 degrees?
Yes. A 12/12 pitch is one inch of rise for each inch of horizontal run, which produces a 45 degree angle and a slope multiplier of about 1.414.
Keep the pitch workflow connected.
Check out the free roofing pilot.
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