Roof Pitch Calculator
Calculate roof pitch with explicit inputs and a worked example.
Formula
- Use the units shown beside each field.
- Results update automatically whenever you change an input.
- Displayed values use up to four decimal places, or scientific notation for very small or large numbers. Calculations use standard floating-point arithmetic; exact integer and fraction tools identify their own precision rules.
- Quantity estimate only. Check dimensions, waste and product coverage for the actual project.
Example Calculation
- Rise: 3 m
- Horizontal run: 4 m
A rise of 3 over a run of 4 is 75%, about 36.87°, or 9 in 12.
Frequently asked questions
How do I use this calculator?
Enter rise, horizontal run. The result updates automatically. Use Reset to restore the example values.
What method does it use?
slope = rise/run; angle = atan(slope); pitch = 12 × slope. Quantity estimate only. Check dimensions, waste and product coverage for the actual project.
Why might a rounded result differ?
The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.
Are my inputs saved online?
No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.
Check the assumptions and units before using this result. Read about calculation methods.