How to use the Roof Pitch Calculator

Convert roof rise and run into pitch in 12, angle in degrees and slope length multiplier.

Calculation formula

Pitch = rise ÷ run × 12 (rise per 12); slope angle = atan(rise/run) in degrees; rafter multiplier = hypot(run,rise)/run.

Recommended steps

1. Enter values using the units shown beside each field.
2. Review whether the example assumptions match your situation.
3. Run the calculator and compare the key metrics.
4. Use the source data or official rates when precision matters.

Known limitations

Slope applies to a straight roof plane. Do not use for structural engineering or code verification.