Roof pitch calculator
Convert roof rise and run into degrees, ratio and slope, and get the rafter length.
Check minimum pitches for your roofing material with the manufacturer.
How this calculator works
Pitch = arctan(rise ÷ run). Rafter length = √(rise² + run²). Multiply the plan area by the roof area factor to get the actual roof surface for one plane.
Worked example: a 600 mm rise over a 2,400 mm run is a 14.0° pitch (3 in 12), with a 2,474 mm rafter before the overhang, and a factor of 1.031.
You may also like…
🧮
Paint calculator
Estimate how many litres of paint you need for a room.
🧮
Tile calculator
Work out how many tiles to buy for a floor or wall, including waste.
🧮
Concrete volume calculator
Calculate the volume of concrete for a slab, path or footing.
🧮
Flooring calculator
Estimate flooring area and the number of packs to buy.
🧮
Soil and mulch calculator
Work out how much soil or mulch to spread over a garden bed.
🧮
Gravel and crushed rock calculator
Calculate the metric tonnes of gravel, roadbase or crushed rock needed for a driveway or p…