A hip roof has slopes on all four sides, meeting at the top at a ridge (for rectangular buildings) or a point (for square buildings). Unlike a gable roof, there are no vertical end walls. Hip roofs are more wind-resistant and aesthetically versatile, but more complex and expensive to build.

How do you calculate the area of a hip roof?

A hip roof on a rectangular building has two trapezoidal slopes and two triangular end slopes. Total area = 2 × (trapezoid area) + 2 × (triangle area), all multiplied by the pitch factor. The calculator handles this geometry automatically — just enter building length, width, and pitch.

What is a hip rafter?

A hip rafter runs diagonally from each corner of the building up to the end of the ridge board. It is longer than common rafters and set at a compound angle. Hip rafter length = √(Run² + Run² + Rise²) where run is the common rafter run, or more practically: Common Run × √2 × Pitch Multiplier.

Does a hip roof cost more than a gable roof?

Yes, typically 20–40% more for the framing due to the complexity of hip rafters and the shorter ridge. However, hip roofs are more durable in high-wind areas and may reduce insurance premiums in hurricane zones, partially offsetting the higher upfront cost.

How many shingles do I need for a hip roof?

Calculate total hip roof area (this calculator does that), divide by 100 for squares, multiply by 3 for bundles (standard architectural shingles), then add 15–20% waste factor (hip roofs waste more than gable roofs due to angled cuts along hip lines).

Hip Roof Calculator

Calculate total area, hip rafter length, ridge length, and complete material estimates for a four-sided hip roof from building length, width, and pitch.

Hip Roof Dimensions

Building Length (ft)?

Building Width (ft)?

Roof Pitch?

Eave Overhang (ft)?

Total Roof Area

1,503 sq ft

Roofing Squares15.03 sq

Main Slopes (×2)930 sq ft

Hip Slopes (×2)572 sq ft

Footprint1,344 sq ft

Ridge Length10.0 ft

Hip Rafter Length24.0 ft

Common Rafter17.9 ft

Pitch Multiplier1.118×

Area Breakdown

2× Main trapezoidal slopes (42.0' × 17.9' slant avg)930 sq ft

2× Hip triangular slopes (32.0' base × 17.9' slant)572 sq ft

Total roofing area1,503 sq ft

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How to Use This Calculator

A hip roof is more geometrically complex than a gable roof. This calculator handles all the trigonometry automatically:

Building Length — The longer footprint dimension (parallel to the ridge)
Building Width — The shorter footprint dimension (perpendicular to the ridge)
Roof Pitch — The common rafter pitch (rise over 12 inches). Hip roofs use this pitch for all common rafters — hip rafters are automatically computed at a shallower angle.
Overhang — Eave overhang distance (horizontal)

The output includes: total roof area, ridge length, hip rafter length (each of 4), common rafter length, valley length (if any), roofing squares, and shingle bundles with waste.

The Formula

Ridge Length = Building Length - Building Width
Common Run = Building Width / 2
Common Rafter Length = Common Run × Pitch Multiplier

Hip Run = √(Common Run² + Common Run²) = Common Run × √2
Hip Pitch Multiplier = √(1 + (pitch/12)² / 2)
Hip Rafter Length = Hip Run × Hip Pitch Multiplier

Two Trapezoidal Slopes Area = 2 × ((Ridge + Building Length) / 2) × Common Rafter Length
Two Triangular End Slopes = 2 × (Common Rafter Length × Common Run / 2)
Total Roof Area = Trapezoid Areas + Triangle Areas

Example: 40 x 24 ft Hip Roof at 5/12

Example: 40 ft long, 24 ft wide, 5/12 pitch hip roof

Ridge Length40 - 24 = 16 ft

Common Run24 / 2 = 12 ft

Common Rafter12 × 1.083 = 13.0 ft

Hip Run12 × 1.414 = 16.97 ft

Hip Rafter Length~17.7 ft (each)

Long Slope Area (each)(16 + 40) / 2 × 13.0 = 364 sq ft

End Triangle (each)13.0 × 12 / 2 = 78 sq ft

Total Roof Area2(364) + 2(78) = 884 sq ft

With 15% waste for the hip cuts, order 11.3 squares (34 bundles) of shingles. Hip roofs use more material per sq ft of footprint than gable roofs because of the angled cuts along each hip line.

Frequently Asked Questions

A gable roof has two sloped sides and two vertical triangular ends (gables). A hip roof has four sloped sides with no vertical ends. Hip roofs are stronger in wind, look more refined, but cost more and provide less attic space.

Start by installing the ridge board. Install the four hip rafters running from each corner to the ends of the ridge. Fill in common rafters between hips. Install jack rafters — shortened common rafters that run from the top plate to a hip rafter. This calculator gives you all the lengths needed.

Every shingle along a hip line must be cut diagonally, creating waste. Also, hip roofs require ridge cap shingles along all four hip lines plus the ridge, compared to just the ridge on a gable roof. Use a 15–20% waste factor for hip roofs vs. 10% for simple gables.

The hip rafter plumb cut angle = arctan(Rise / (Run × √2)). For a 6/12 common pitch: angle = arctan(6 / (12 × 1.414)) = arctan(0.354) = 19.47°. This is the backing angle needed for proper seating of hip jack rafters.

In most cases, hip roofs cost less to insure than gable roofs in wind-prone areas. Insurance companies in Florida and other hurricane states often offer discounts for hip roofs because they perform better in high winds. Check with your insurer for specific credits.

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Sources & References

The formulas, code requirements, and reference data used in this calculator are sourced from the following authoritative organizations and publications. Local codes vary — always verify with your jurisdiction's building department.

International Residential Code (IRC) 2024 — Chapter 9: Roof Assemblies — ICC
NRCA Roofing Manual (Steep-Slope & Low-Slope) — National Roofing Contractors Association
Asphalt Shingle Installation Manual — ARMA (Asphalt Roofing Manufacturers Association)
GAF Roof Measurement Guide — GAF
NRCA Project Pricing Guidelines — NRCA

Disclaimer: Calculator results are estimates intended for planning and educational purposes only. They do not replace professional engineering analysis, building permit review, or contractor estimates. Always consult a licensed roofing contractor or structural engineer for final specifications.