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Roofing Calculator

Estimate roof area, roofing squares, asphalt shingle or metal waste, underlayment rolls, nails, ridge caps, starter strips, valleys, and hips.

Published

Total area
Area with allowance
696 ft²
Bundles needed
21 bundles
Geometry area before allowance
632.46 ft²
Waste factor
10%
Section Breakdown
Section 1
632.46 feet²

Geometric takeoff only. Pitch multiplier is calculated from rise/run; verify entered product coverage and waste. No installation, code, or fall-safety conclusion is provided.

Measurement Unit
Section
Section 1
%
ft²

Results update as you type.

Roofing Calculator

Estimate roof area, roofing squares, asphalt shingle or metal waste, underlayment rolls, nails, ridge caps, starter strips, valleys, and hips.

Inputs and method

Enter plan dimensions and rise/run for each section, plus waste and manufacturer-stated bundle coverage. Surface area uses the calculated multiplier √(1 + (rise/run)²); waste is applied once before whole-bundle rounding.

Calculations retain full floating-point precision until the labeled display step. Counts and packages use an explicit upward ceiling only where a whole purchase unit is required.

Interpreting the estimate

Use the result as a planning value and keep input precision consistent with the measurements or source data you have. Small displayed differences can come from final-place rounding; intermediate values are not rounded.

Assumptions and limits

Openings, hips, valleys, starter, ridge, flashing, installation, fall protection, and local requirements need a separate takeoff and review. The result is not a product or safety recommendation.

Empty entries, invalid numbers, prohibited negatives, zero denominators, impossible relationships, and unsupported options trigger a validation message instead of a misleading result.

Sources

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Roofing Calculator updated at