Roof Area Calculator

Roofing tip: While estimating shingles for a sloped roof, I used the roof area calculator to compute rectangular and triangular sections separately. Once I added pitch adjustments, the totals were spot on. For dormers and other shapes, I used the area calculator since it supports triangles, sectors, and trapezoids.

This roof area calculator estimates the surface area of various roof types including gable, hip, shed, pyramid, gambrel, and conical roofs. Formulas are provided below.

Gable Roof
The area of a gable roof is A = 2 × (base × height), where base is the width of the building and height is the slant height of the roof. For a roof 30 ft wide with 10 ft slant height, the calculator gives A = 2 × (30 × 10) = 600 ft².

Hip Roof
The area of a hip roof is estimated using A = length × width + 2 × (hip height × eaves length), where hip height is measured from eaves to ridge. For a roof 40 ft long, 30 ft wide, and hip height of 6 ft with 25 ft eaves, the calculator computes A = 40 × 30 + 2 × (6 × 25) = 1200 + 300 = 1500 ft².

Shed Roof
The area of a shed roof is A = length × slant height, where slant height is the diagonal roof surface. For a 20 ft long roof with 12 ft slant height, the calculator returns A = 20 × 12 = 240 ft².

Pyramid Roof
The area of a pyramid roof is A = 2 × base × slant height, assuming four equal triangular sides. For a square base of 16 ft and slant height of 10 ft, the calculator gives A = 2 × 16 × 10 = 320 ft².

Gambrel Roof
The area of a gambrel roof is estimated by splitting it into two trapezoids per side and using A = 2 × ½ × (upper base + lower base) × height. For upper base = 8 ft, lower base = 12 ft, height = 7 ft: A = 2 × ½ × (8 + 12) × 7 = 2 × 10 × 7 = 140 ft².

Conical Roof
The area of a conical roof is A = π × r × l, where r is the base radius and l is the slant height. For a conical roof with r = 5 m and l = 9 m, the calculator returns A = π × 5 × 9 = 45π ≈ 141.37 m².