Calculate the total surface area of a hip roof from building dimensions and pitch. Estimate shingles, underlayment, and ridge cap materials.
A hip roof slopes on all four sides, meeting at a ridge (for rectangular buildings) or a single peak (for square buildings). Hip roofs are popular for their wind resistance and clean appearance, but calculating their area is more complex than a simple gable because the roof consists of two trapezoidal planes and two triangular planes.
This hip roof area calculator simplifies the process by taking your building's length, width, and uniform pitch. It computes the area of each face, sums them, and applies a waste factor so you can order shingles, underlayment, and accessories with confidence.
Accurate hip roof area estimation is critical for contractors preparing bids and homeowners budgeting a re-roof. The hip configuration generates more waste than a gable due to the angled cuts along hip lines, so a slightly higher waste factor (12–15%) is recommended.
This measurement supports better project estimation, enabling contractors and engineers to deliver accurate bids and avoid costly overruns during the construction process.
Hip roofs have four sloping faces with diagonal hip lines that complicate manual area calculations. A small math error multiplied across four faces can lead to significant material shortages or overages. This calculator eliminates guesswork, giving you the true surface area in seconds so you can order the right quantity and budget accurately.
Slope Factor = √(1 + (pitch/12)²) Hip Factor = √(1 + (pitch/12)² + 1) [diagonal] For a rectangular hip roof: Ridge Length = Building Length − Building Width Two Trapezoids: Area each = ((Ridge Length + Building Length) / 2) × (Width/2) × Slope Factor Two Triangles: Area each = (Building Width / 2) × (Width/2) × Slope Factor Total = 2 × Trapezoid + 2 × Triangle Simplified: Total = Building Length × Building Width × Slope Factor
Result: 1,878.2 sq ft (adjusted)
Slope factor = √(1 + 0.25) = 1.1180. Footprint area = 50 × 30 = 1,500 sq ft. Sloped area = 1,500 × 1.1180 = 1,677.1 sq ft. With 12% waste: 1,677.1 × 1.12 = 1,878.3 sq ft, or about 18.78 roofing squares.
A hip roof on a rectangular building has four faces: two trapezoids along the long sides and two triangles at the short ends. The diagonal lines where adjacent slopes meet are called hip lines. These hip lines run from each corner of the eave to the end of the ridge. On a square building, all four faces are identical triangles and there is no ridge — the roof forms a pyramid.
The slope factor method multiplies the footprint area by √(1 + (pitch/12)²). This works because every unit of horizontal footprint corresponds to a larger sloped surface. The beauty of this approach is that it applies uniformly to any roof shape as long as all faces share the same pitch. For a uniform-pitch hip roof, total sloped area = footprint area × slope factor.
Beyond field shingles, a hip roof requires hip and ridge cap shingles, which are either pre-formed or cut from standard shingles. Measure all four hip lines and the ridge to determine cap quantity. Also order enough starter strip for the full eave perimeter (all four sides), not just two sides as with a gable.
A hip roof has slopes on all four sides, and each side meets neighboring sides along diagonal hip lines. On a rectangular building, two faces are trapezoids and two are triangles. Hip roofs are common in hurricane-prone regions because their aerodynamic shape resists wind uplift better than gables.
The footprint is the horizontal projection. Because every square foot of footprint is tilted upward at the roof pitch, the true surface area is always larger. The slope factor converts footprint to actual sloped area.
A simple gable typically produces 10% waste, while a hip roof produces 12–15% due to the diagonal hip lines. Shingles must be cut at angles along these lines, creating unusable offcuts.
This calculator assumes a uniform pitch on all four sides. For mixed-pitch hips, calculate each face individually using the appropriate pitch and slope factor, then sum the areas.
For a standard rectangular hip roof, the ridge length equals the building length minus the building width. A 50 ft × 30 ft building has a 20 ft ridge. If the building is square, the ridge length is zero.
Yes. Hip cap shingles cover the four diagonal hip lines and the center ridge. Measure each hip line length (approximately width/2 × hip factor) and the ridge, then order cap shingles to cover that total linear footage.
A Dutch hip has a small gable above the hip at each end. This calculator works for a full hip — for a Dutch hip, subtract the gable triangle area and add the corresponding gable roof area. A separate Dutch gable calculator may be more convenient.
Divide the adjusted area by 100. For example, 1,878 sq ft ÷ 100 = 18.78 squares. Round up to 19 squares for ordering.