Roofing calculator
You don’t need to climb up there. Measure the house from the ground, pick the roof pitch, and the calculator works out the sloped area.
Roofing squares
16.53 squares
- Shingle bundles
- 50 bundles
- Roof area
- 1,503 sq ft (before waste)
- Pitch factor
- 1.118 × footprint
How it works
A sloped roof has more surface than the ground it covers. The calculator measures the footprint including the overhang on all four sides, then multiplies by the pitch factor: √(1 + (rise ÷ 12)²). A 6/12 roof, for example, has 1.118 times the area of its footprint.
That works for gable and hip roofs alike, as long as every section has the same pitch. A roofing square is 100 square feet. Most shingles come three bundles to a square, but check the wrapper.
Example
With house length 40 ft, house width 30 ft, eave overhang 12 in, roof pitch: 6/12, waste 10%, bundles per square 3, the answer is 16.53 squares.
Tips before you buy
- Order ridge cap and starter strip separately. They aren’t included in the field shingle count.
- Garages, porches and dormers with a different pitch should be calculated separately and added.
- To find the pitch, hold a level horizontally against a rafter, measure 12 inches along it, and measure straight up to the rafter. That rise is your pitch.
- Many roofers use 15% waste on hip roofs because of all the angled cuts.
Common questions
What is a roofing square?
100 square feet of roof surface. A 2,000 square foot roof is 20 squares.
How many bundles of shingles are in a square?
Usually three for standard 3-tab and most architectural shingles. Some heavier designer shingles take four or five.
Does a hip roof need more shingles than a gable roof?
Not more area if the pitch is the same, but hips create more cutting waste, and you’ll need more ridge cap.