Roofing Calculator

Estimate roofing squares from building footprint and pitch.

Roofing Calculator helps you roof squares from footprint, pitch multiplier, and waste. Enter footprint length, footprint width, pitch rise (in per 12 run), and waste, review the breakdown, and use the guidance below to understand what the number means — and what it does not. What the Roofing calculator does Roofing Calculator is built for materials, areas, volumes, and jobsite estimates. Roof squares from footprint, pitch multiplier, and waste. You enter footprint length, footprint width, pitch rise (in per 12 run), and waste, then Simple Calculators computes the result instantly. Formulas match common contractor and DIY references for rectangular and simple shapes. How the math works Plan area × pitch factor × (1 + waste). Pitch factor ≈ √(1 + (rise/12)²). Squares = surface ft² / 100. The formula: Squares = length × width × √(1 + (rise ÷ 12)²) × (1 + waste) ÷ 100. The square-root part is the pitch factor: how much bigger a sloped roof is than its flat footprint. One square = 100 ft².