Rise and run in, real roof math out — x/12 pitch, angle, slope, multiplier, and rafter length. Pair it with the roofing calculator to turn footprint into a full material order.
Ballpark, not gospel. This converts the rise and run you enter into pitch math — verify pitch on the roof itself with a level and tape before ordering, since sag and settled framing can fool a measurement.
Straight answers, no fluff. Then run your own numbers above.
Divide the rise by the run and multiply by 12 — that's your x/12 pitch. A roof that climbs 7 inches over a 12-inch run is a 7/12. Enter any rise and run above and the calculator converts it to pitch, angle degrees, slope percent, and the multiplier.
The multiplier converts a roof's footprint area into true surface area: multiply any footprint square footage by it. For a 7/12 pitch the multiplier is 1.158 — a 1,500 sq ft footprint is really 1,737 sq ft of roof. That number drives material orders and pricing.
Up to 4/12 is generally walkable with standard fall protection. Steeper than 6/12, most crews stage the roof or use roof jacks and safety lines — and expect 10–20% more labor on the bid for anything above 8/12.
Multiply the pitch multiplier by half the building span: a 28-foot span on a 7/12 pitch needs a 16.2-foot common rafter before the ridge cut and tail. The calculator above computes this for any span you enter.
Related guides: Roofing Calculator · Roof Installation Cost · Roof Replacement Cost · Bundles Per Square
Got your pitch? Turn this measurement into a professional roofing quote and send it before you leave the job site.