Roof Shingle & Square Calculator
Convert ground footprint and pitch into actual slope area, shingle bundles, starter strips, and ridge caps.
House Footprint & Pitch
Frequently Asked Questions
How many bundles of shingles are in 1 roofing square?
One roofing square equals 100 square feet. For standard architectural and 3-tab asphalt shingles, there are exactly 3 bundles per square. (Special heavyweight luxury shingles may require 4 or 5 bundles per square).
How do you calculate roof shingles from ground footprint?
Measure the length and width of your house footprint, add twice the eave/rake overhang to each dimension, multiply by the roof pitch multiplier (e.g. 1.118 for a 6:12 pitch) to find true roof surface area, add 10% to 15% for waste and valleys, divide by 100 to get Squares, and multiply Squares by 3 to get Bundles.
How much underlayment do I need?
Synthetic roof underlayment typically comes in 10-square rolls (1,000 sq ft). Divide your total roof squares by 10 and round up to the nearest whole roll.
Deep dive: How many bundles of shingles per square, and what pitch and hip roofs do to the count.
Read the guide →Embed This Calculator on Your Site
Add this shingle estimator to your blog, roofing supplier site, or client portal for free. Copy the snippet below — the widget updates automatically and links back to the full version.
<iframe src="https://calcbuilders.com/roofing/shingles/embed/" width="100%" height="780" style="border:0;border-radius:12px" title="Roof Shingles Calculator"></iframe>Height 780px fits the full widget; trim to ~540px for just the form. Preview the widget →