Roofing Calculators

How many roof trusses do I need? Free calculator for 600 mm standard spacing — enter roof length for instant truss count and layout.

Rafter calculator: Estimate rafter count by roof length & spacing. Free tool for 400 mm and 600 mm centres — works for gable and hip roofs.

Ridge board calculator: How many boards for my roof peak? Free tool for standard ridge board sizes — gives length and count.

How many OSB sheets to sheathe my roof? Free roof decking calculator for 1200×2400 mm panels — factors in roof pitch and waste.

Shingle calculator: How many bundles do I need? Free estimator for standard shingles — converts square metres to bundles.

How many rolls of roofing underlayment? Free calculator for breathable membrane & felt — accounts for overlap and waste.

Drip edge calculator: Estimate linear metres of flashing for your roof. Free tool — gives piece count for standard drip edge strips.

What pitch is my roof? Free roof pitch calculator — enter rise & run for instant angle, slope %, and area multiplier.

Roof area calculator: Convert flat dimensions to actual roof area. Free tool — accounts for pitch multiplier, gives roofing squares.

How steep is my roof? Free slope calculator — measure rise & run to get pitch ratio, angle, and recommended roofing material type.