Roof Pitch Calculator
A 6 inch rise in a 12 inch run is 6.00/12, 26.57 degrees, a 1.118 multiplier, and a 50.00 percent slope.
Last updated . Rise and run start in inches. Switch them to millimeters or centimeters. Degrees and x/12 write the rise for you. No price.
Enter rise and run, or degrees, or the x in x/12. The multiplier is the factor for roof area.
Roof area: roofing calculator. Bundles: shingle calculator.
Pitch, degrees, and multiplier
Type a rise and a run, or a degree angle, or the x in x/12. Changing x sets the run to 12 in the same unit as the rise. The multiplier is the roof-area factor.
Results
How the pitch is converted
x/12 = (rise ÷ run) × 12. Degrees = atan(rise ÷ run). The multiplier = sqrt(1 + (rise ÷ run)²). Percent slope = (rise ÷ run) × 100. For 6 and 12 the ratio is 0.5, so the pitch is 6.00/12, the angle is 26.57 degrees, the multiplier is 1.118, and the slope is 50.00 percent.
Typing degrees keeps the run and sets the rise to run × tan(degrees). Typing x sets the run to 12 in the rise’s unit and sets the rise to x. The roofing page uses this same multiplier on the plan area.
Pitch multiplier table
These rows are the same conversion. Set the rise to the first number and the run to 12 to read them on the tool.
| Pitch | Degrees | Multiplier | Percent |
|---|---|---|---|
| 3.00 / 12 | 14.04° | 1.031 | 25.00% |
| 4.00 / 12 | 18.43° | 1.054 | 33.33% |
| 6.00 / 12 | 26.57° | 1.118 | 50.00% |
| 8.00 / 12 | 33.69° | 1.202 | 66.67% |
| 9.00 / 12 | 36.87° | 1.250 | 75.00% |
| 12.00 / 12 | 45.00° | 1.414 | 100.00% |
Frequently asked questions
What is a 6/12 pitch in degrees?
Leave the rise at 6 in and the run at 12 in. Pitch reads 6.00 / 12. Degrees read 26.57°. Multiplier reads 1.118. Percent reads 50.00%. The multiplier is sqrt(1 + 0.5²), and 0.5 is 6 ÷ 12.
What is an 8/12 pitch?
Set the rise to 8 and leave the run at 12. Pitch reads 8.00 / 12. Degrees read 33.69°. Multiplier reads 1.202. Percent reads 66.67%. That multiplier is what the roofing page would use on the plan area.
How do I enter 45 degrees?
Set degrees to 45. With the run still at 12, the rise becomes 12. Pitch reads 12.00 / 12. Degrees read 45.00°. Multiplier reads 1.414. Percent reads 100.00%. A 12/12 pitch is 45 degrees, and the factor is sqrt(2).
How do I enter 4/12 directly?
Type 4 in the x/12 field. The run resets to 12 in the same unit as the rise, and the rise becomes 4. Pitch reads 4.00 / 12. Degrees read 18.43°. Multiplier reads 1.054. Percent reads 33.33%.
What does the multiplier do?
Roof area = plan area × multiplier. The plan is flat. The multiplier stretches it to the slope. For 6/12 it is 1.118, so 100 square feet of footprint is 111.80 square feet of roof before overhang and waste. The roofing calculator applies it to the footprint after the overhang.
Why is 9/12 exactly 1.250?
A 9 inch rise in 12 inches is 0.75. The multiplier is sqrt(1 + 0.75²) = sqrt(1.5625) = 1.25, which prints as 1.250. Degrees are 36.87°. Percent is 75.00%. Set the rise to 9 and the run to 12 to read those lines.
Is this the shingle order?
No. This page converts rise, run, degrees, and the area factor. Squares and waste are the roofing calculator. Bundles, starter, and ridge cap are the shingle calculator.