Roofing Calculators
Estimate all roofing materials from trusses and rafters to tiles, slates, and underlayment.
Free roof truss calculator — get truss count & spacing for any roof length. Enter span for 600 mm centres layout, cost estimate & tips.
Free rafter calculator — get rafter length, count & spacing for any roof type. Covers 400 mm and 600 mm centres for gable & hip roofs.
Ridge board calculator UK: What size ridge board do I need? Free tool for C16/C24 softwood sizing — board count, length, and 2026 timber prices.
How many OSB sheets to sheathe my roof? Free roof decking calculator for 1200×2400 mm panels — factors in roof pitch and waste.
Free shingle calculator for roof shingles — get bundles, squares & cost from square metres. Covers standard & architectural shingles.
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.
Free roof area calculator — convert flat dimensions to true roof area using pitch multiplier. Get roofing squares & material estimates.
Roof slope calculator — free tool to find pitch, angle, and sloped roof area multiplier. Enter rise & run for instant results in metres and degrees.
Free hip roof calculator — get rafter count, hip rafter length, roof area & ridge length. Covers common, hip & jack rafters for any building size.
Free gambrel (barn) roof calculator — get upper & lower rafter counts, roof area & wall height gained. Enter two pitches for instant results.
Free gable roof calculator — get rafter count, ridge length, roof area & gable end area. Enter building dimensions and pitch for instant estimate.
Free lean-to (shed) roof calculator — get rafter count, rafter length, roof area & rise height. Single-slope calculator for extensions & sheds.