Key takeaways
- A hip roof has the same area as a gable roof with the same footprint and pitch.
- What changes is the edges: four hips and a shorter ridge.
- Hips usually call for more cutting, so GAF's waste range of 10–15% matters here.
Enter the house's size, pitch and overhang. This suits a regular hip roof: four planes at one pitch, meeting at one ridge.
How the calculator works
- Area: footprint × slope multiplier
- Ridge: longer side − shorter side
- Run: half the shorter side
- Rise: run × pitch ÷ 12
- Each hip: √(2 × run² + rise²)
- Eaves: the perimeter of the footprint
This is our own geometry, and you can check it by hand. A hip runs diagonally across the corner, which is why the run counts twice inside the square root.
Worked example
A 40 × 30 foot house at 6/12, with no overhang:
- Area: 1,200 × 1.118 = about 1,342 square feet
- Ridge: 40 − 30 = 10 feet
- Run: 15 feet, and rise: 7.5 feet
- Each hip: √(2 × 225 + 56.25) = 22.5 feet
- Ridge and hips together: 10 + 4 × 22.5 = 100 feet
- Eaves: 140 feet
Hip or gable: what really changes
For this same house at 6/12:
| Hip roof | Gable roof | |
|---|---|---|
| Roof area | 1,342 sq ft | 1,342 sq ft |
| Ridge | 10 ft | 40 ft |
| Hips | 90 ft | None |
| Eaves | 140 ft | 80 ft |
| Rakes | None | About 67 ft |
Area is the same, so shingle quantity differs mainly through waste and cap material. Hips call for angled cuts, and GAF says features like these need more material than the square footage suggests, with a general 10–15% allowance. A roofer's takeoff should replace our estimate.
What this leaves out
- Mixed shapes: dormers, valleys, and L-shaped or mixed-pitch roofs need separate work. Split them into sections with the roof area calculator.
- Framing: this doesn't size hip rafters or check their loads. That comes from your local code or an engineer.
- Cap coverage: ridge cap coverage varies by product, so use its label to turn feet into bundles.
Then count bundles with the shingle calculator.
Frequently asked questions
How do I calculate the area of a hip roof?
Multiply the footprint by the slope multiplier for your pitch, as long as all planes share one pitch.
Does a hip roof need more shingles than a gable?
The surface is the same for the same footprint and pitch. Extra cuts and cap material usually add to your order.
How long is the ridge on a hip roof?
For a regular hip roof, the longer side minus the shorter side. A square footprint has no ridge, and the hips meet at a point.
Sources
We use primary sources where we can: building codes, federal rules and manufacturer documents. Read our editorial standards.