Roof Pitch Calculator
Calculate x:12 pitch, degrees, slope percentage, multiplier, common rafter and ridge length, gable roof area, overhangs, and waste in feet or meters.
Pitch input
Roof measurements
Results
- Pitch
- 6:12
- Angle
- 26.57°
- Slope
- 50%
- Slope multiplier
- 1.12×
- Measured slope length
- 13.42
- Common rafter length
- 17.89 ft
- Ridge length
- 42 ft
- Roof surface area
- 1,502.64 ft²
- Area with waste
- 1,652.9 ft²
Estimate for a symmetrical gable roof. Confirm structural dimensions and local requirements with a qualified professional.
This tool is still being fine-tuned, so you may run into the odd error. Spotted one? Let us know so we can fix it.
What is Roof Pitch Calculator?
Calculate roof pitch online from rise and run or degrees. Get x:12 pitch, slope percentage, multiplier, common rafter length, ridge length, and gable roof area.
How to calculate roof pitch
Convert rise and run or an angle into x:12 pitch, degrees, slope percentage, rafter length, and roof surface area.
Pitch conversions
A 6:12 pitch rises 6 units for every 12 units of horizontal run. That equals a 50% slope and an angle of about 26.57 degrees. The slope multiplier converts horizontal distance into sloped distance.
Roof area
For a symmetrical gable roof, the calculator adds eave and gable overhangs, calculates both roof planes, and then applies the selected waste allowance.
How to use it
- Enter measured rise and run, or switch to an angle.
- Choose feet or meters and enter building dimensions.
- Add eave and gable overhangs.
- Review pitch, rafter, ridge, area, and area with waste.
Calculated locally
All roof dimensions and calculations remain in your browser and are never uploaded.
Frequently Asked Questions
What does 6:12 roof pitch mean?
The roof rises 6 units for every 12 units of horizontal run. The units can be inches, centimeters, or any consistent measurement.
Does roof area include both sides?
Yes. The area result covers both planes of a symmetrical gable roof, including entered overhangs.
Can I use the result to cut structural rafters?
Use it as an estimate only. Cuts, ridge thickness, structural loads, codes, and field conditions require project-specific verification by a qualified professional.