Hip Roof Calculator
Calculate hip roof area from the building footprint and pitch, using the same slope-multiplier method as a gable roof.
How this calculator works
A hip roof slopes on all four sides instead of just two, but for the purpose of estimating total roof surface area, it’s calculated the same way as a gable roof: take the flat footprint and scale it up by a multiplier based on pitch. This calculator finds that multiplier from your pitch, then applies it to your footprint’s length and width.
Formula: Roof area = footprint length × footprint width × area multiplier, where the multiplier = 1 ÷ cos(arctan(pitch ÷ 12)).
Worked example
A 40 ft × 30 ft footprint with a 6-in-12 pitch:
- Area multiplier: ≈ 1.118
- Roof area: 40 × 30 × 1.118 ≈ 1,341.64 sq ft
Notes
A hip roof’s total surface area comes out very close to a gable roof of the same footprint and pitch, since both shapes use the same slope multiplier to convert footprint into roof area. The real difference between hip and gable is the roof’s shape — a hip roof slopes on all four sides instead of two.
That shape difference affects hip rafter length and framing complexity, which are structural concerns, not the area figure used for ordering shingles. If you need framing details, that’s a separate calculation from the one here.
How to use
Enter your building’s footprint length and width along with your roof’s pitch. The calculator works out the area multiplier for that pitch and returns the total roof surface area for shingle ordering.
A geometric area estimate. Confirm actual roof dimensions on site — hip roofs have additional hip and valley flashing not captured by a simple area figure.
Frequently asked questions
Does a hip roof need more shingles than a gable roof?
Not for the same footprint and pitch — both shapes use the same area multiplier, so the total sloped surface area comes out very close either way. The real difference between hip and gable roofs is framing complexity, not the amount of roofing material for the field of the roof.
What is the area multiplier in this formula?
It's a factor that converts your flat footprint area into sloped roof area, based on your roof's pitch. A steeper pitch produces a larger multiplier because the roof surface is angled further from flat, so the same footprint requires more actual roofing material to cover it.
What footprint dimensions should I use?
Use your building's overall length and width at the roofline, not the interior floor dimensions. If your roof overhangs the walls, measure to the outer edge of the roofline, since that's the footprint the roof actually needs to cover.
Why doesn't this calculator account for hip and valley framing?
It calculates the roof's surface area for shingle ordering, which is driven by footprint and pitch. Hip rafter lengths and additional framing complexity from the four sloped sides are a separate structural calculation and don't change the total shingle-coverage area.
Estimates only. Verify quantities with your supplier before purchasing.