About Roofing Calculator

Getting a roof estimate shouldn't require handing over your email, booking a sales call or downloading questionable software. Yet that's what most "free" roofing calculators ask you to do.

We built Roofing Calculator to change that. The math runs entirely in your browser, and there's no account to create. You can leave a phone number if you want a roofer to call you back, but it's optional and you get the full results either way. Enter your roof dimensions, pick a material and get a detailed breakdown of area, materials and cost in under two minutes.

The calculator uses pitch-adjusted geometry to convert the flat footprint into actual roof surface area. Waste depends on the roof: a gable starts at 10%, a hip at 15%, and valleys and dormers add their own cut-offs on top. It counts bundles and rolls for each piece (shingles, underlayment, ridge cap, starter course), then prices the job from national average cost ranges. Add a ZIP code and the labor side shifts to match roofer wages in your state. That gives you a realistic budget before you talk to a contractor.

If you only need one number, there's a set of free standalone calculators for that: roof pitch, shingle bundles, attic ventilation, gutters, flat roofs, metal panels, sheathing, and whether to repair or replace. They don't need a sign-up either.

We also maintain a library of in-depth roofing guides covering topics from roof pitch basics to metal vs. shingle comparisons, written to help you make informed decisions about one of the biggest investments in your home.