Free · No sign-up · Every formula shown
Roofing calculators that show their working
Pitch, area, rafters, materials, cost and load — measured the way roofers and framers actually work, in imperial or metric, with every step of the math on screen.
Your measurements
Enter the values you know — results update live.
Vertical height the roof gains. Measure from the top of the wall plate to the underside of the ridge.
Horizontal distance the rise happens over. For an X:12 pitch, use 12.
Analysis
Live results from your measurements.
Pitch (rise per 12)
6:12
Angle
26.57°
Slope
50%
Pitch multiplier
1.118
Rafter per unit of run
13.416
Walkable with care. Most crews still use roof jacks and a harness.
Show the working
- Slope ratio:
6 ÷ 12= 0.5 - Pitch as X:12:
0.5 × 12= 6:12 - Angle:
arctan(0.5)= 26.57° - Slope percentage:
0.5 × 100= 50% - Pitch multiplier:
√(6² + 12²) ÷ 12= 1.118