Roof Pitch & Rafter Calculator

A roof pitch calculator and rafter calculator for framing and roofing, in feet, inches and fractions or in metres. Work out rafter length, roof angle, hip and valley rafters, roof square footage and how many shingle bundles to buy. Free, offline, no account. PITCH AND ANGLE • Pitch from rise and run, or convert any pitch (6:12, 7 1/2:12), angle or grade • Roof angle in degrees, grade %, slope factor (pitch multiplier) • Rafter-table figures per foot of run, as on a framing square: 6:12 gives 13.42" common and 18.00" hip or valley RAFTER LENGTH CALCULATOR • Common rafter length from the span or the run, with overhang and ridge board deduction • Answers to the nearest 1/16": plate to ridge, overhang tail and total length to cut • Plumb cut and seat (level) cut angles for your speed square • Ridge height above the plate • Regular hip and valley rafter length and hip pitch ROOFING CALCULATOR • Roof area from the plan size of a gable or hip roof, overhangs included • Roofing squares and shingle bundles with your waste allowance (3 bundles per square by default) • Underlayment rolls (#15 felt, #30 felt, synthetic or your own roll size) • Drip edge pieces, ridge length, hip lengths and ridge cap MADE FOR THE JOB SITE • Type lengths the way you write them: 12' 6 1/2", 12'6", 6 1/2" or 12.5 • Everything you type is remembered, even if you rotate the phone or close the app • Copy or share any result as text • Light and dark themes, works fully offline No account, no subscription, nothing locked. Free with a small banner ad; an optional one-time purchase removes the ads. Built by Fernhart Labs. Always check measurements on site and the labels on your materials before cutting or ordering.