Step-by-step tutorials explaining the methods, formulas, and techniques behind roof measurement, material estimation, and cost calculation. Each guide links to its matching calculator tool.
Understanding the math behind your roof project helps you verify contractor estimates and plan with confidence.
Learn the rise-over-run method, speed square technique, and ground-level measurement for finding your roof's pitch ratio and angle.
Read GuideMeasure your roof area from ground level using house dimensions, pitch multiplier, overhang, and waste factor calculations.
Read GuideBreak down the cost formula contractors use: materials, labor, tear-off, dump fees, permits, and profit margin per roofing square.
Read GuideConvert roof area to bundles, roofing squares, and accessory materials — starter strips, ridge caps, nails, and underlayment.
Read GuideDetermine panel count, screw quantity, ridge cap, and trim lengths for standing seam, corrugated, and R-panel installations.
Read GuideGeometry formulas for gable, hip, gambrel, mansard, flat, shed, and saltbox roofs — with diagrams and worked examples.
Read GuideUse trigonometry to find rafter length from span and pitch, plus birdsmouth cut depth, HAP, and ridge board height.
Read GuideDetermine truss count, spacing, span limits, height, and member sizes for Fink, King Post, Queen Post, and attic trusses.
Read GuideConvert ground snow load to roof snow load using exposure, thermal, and slope factors per ASCE 7 and IRC building codes.
Read GuideApply the 1/300 and 1/150 rules to determine Net Free Area, then size ridge vents, soffit vents, and power fans.
Read GuideSize gutters and downspouts using drainage area, rainfall intensity, and gutter capacity charts for K-style and half-round.
Read GuideEach guide above links to its matching calculator. Or jump straight to our most popular tools.