How to estimate roofing shingles
Convert roof area to squares, then to bundles, and add waste for cuts and hips/valleys.
Roofing is usually sold in “squares” (100 sq ft). The basic estimate is roof surface area divided by 100, then converted to bundles based on the shingle product.
Waste depends heavily on roof complexity—valleys, hips, dormers, and cut-up layouts increase overage.
Step-by-step: roofing math
- Measure roof surface area (not just the house footprint).
- Convert area to squares (sq ft ÷ 100).
- Add a waste factor (often 10–15%+, more for complex roofs).
- Convert squares to bundles using the product’s bundles-per-square.
- Round up and include starter, ridge caps, and underlayment as separate line items.
Practical tips
- Roof pitch increases surface area—don’t estimate from footprint alone.
- Complex roofs need more waste than simple gables.
- Bundles-per-square varies by shingle type and weight.
- Order extras for repairs or future matching, especially for specialty colors.
Want bundles and squares instantly?
Use our roofing calculator and share a link that keeps your inputs.
FAQ
What is a roofing square?
A roofing square is 100 square feet of roof coverage.
How many bundles are in a square?
Often 3 bundles per square for many asphalt shingles, but it varies—check the product specs.
How much waste should I add for roofing?
10–15% is common. Complex roofs with many valleys/hips may need more.
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