Roofing

Shingle Calculator

How many shingles do I need? Enter your roof area and waste allowance and get bundles and squares — free, no signup.

What do you want to work out?

Footprint length (ft)

Footprint width (ft)

Rise (in)

Run (in)

Estimates only. Roof area is the flat footprint divided by the cosine of the pitch angle — a steeper roof is a bigger roof. Measure each slope separately on a complex roof, add hips, valleys and overhangs, and confirm the final order with your roofer or supplier.

How many shingles do I need?

Roof area divided by bundle coverage, plus waste. One bundle of shingles covers 33.33 sq ft and 3 bundles make one square (100 sq ft). With 10% waste, 1,732.05 sq ft of roof needs 58 bundles — about 19.3 squares, so order 20 squares if you buy by the square.

Use the roof area, not the footprint: a 1,500 sq ft footprint at a 30 degree pitch is 1,732.05 sq ft of roof, so the footprint alone would leave you short. Add 10% waste for a simple gable roof and 15% for a cut-up roof with valleys, hips and dormers.

Working out the roof area from your footprint and pitch? Use the roofing calculator.

How to use the Shingle Calculator

Enter your roof area in square feet (not the footprint).
Set a waste allowance — 10% for a simple roof, 15% for a cut-up roof.
Read off the bundles to buy.
Order by the square: 3 bundles make one square (100 sq ft).

Frequently asked questions

How many shingles do I need for 1,732 square feet of roof?

With 10% waste, 58 bundles. One bundle covers 33.33 sq ft, so 1,732.05 sq ft needs 57.16 bundles before rounding — buy 58 bundles — about 19.3 squares, so order 20 squares if you buy by the square.

How many bundles of shingles are in a square?

3 bundles make one square. One square covers 100 sq ft and one bundle covers 33.33 sq ft.

How much waste should I add for shingles?

10% for a simple gable roof. Use 15% for a roof with lots of valleys, hips and dormers, where more shingles are cut away.

Do I use the footprint or the roof area for shingles?

The roof area — the true sloped surface. A 1,500 sq ft footprint at a 30 degree pitch is 1,732.05 sq ft of roof. Use the roofing calculator to work out the roof area from your footprint and pitch.