Roofing Calculators

Roofing projects fail when the area is wrong. Pitch changes how much surface you actually have, shingles are sold in squares, and installed cost is a range—not a bid. These calculators separate geometry from price: first compute area and pitch, then convert that area into bundles or a cost range using unit prices you can edit. They do not replace a roof inspection, a structural check, or a written contractor proposal. Use them to size materials, sanity-check quotes, and decide whether a repair or a full reroof is even in your budget.

Calculators

How to measure

Measure the building footprint (length × width) from the ground or a scaled plan, not the sloped surface. Note the pitch as rise over run (inches of rise per 12 inches of run). Count distinct roof planes if you have hips, valleys, or a detached garage. For a reroof, also note layers to tear off and any skylights or chimneys that reduce net shingle area.

Related categories

• Solar & Energy
• Home Maintenance
• Remodeling

FAQ

Is roof area the same as house square footage?

No. Living area ignores overhangs and roof pitch. Roof surface area is the footprint (including eaves) multiplied by a pitch factor, plus extra for hips, valleys, and waste.

Can these tools tell me exactly what a new roof will cost?

No. They multiply area by typical US unit-price ranges you can edit. Local labor, decking repairs, permits, and steep or multi-story access can move a bid well outside any national range.

What pitch should I enter if I do not know it?

Many production homes are around 4:12 to 6:12. You can measure rise over a 12-inch run in the attic, or use the roof pitch calculator from a photo only as a rough check—not for ordering materials.