Roofing Calculator

Use this free roofing calculator to estimate roof area, roofing squares, and shingle bundles for a simple pitched roof.

All tools

Research-backed assumptions Formula steps Examples included Private in-browser use

Footprint length feetFootprint width feetPitch rise per 12Waste percent

Estimated roof material14.7580486515 squares

1200 ft2 footprint, 6/12 pitch

Roof area with waste: 1475.80486515 ft2
Pitch factor: 1.1180339888
Bundles: 45

Complex roofs, valleys, hips, dormers, tear-off, and product coverage can change real orders.

Formula steps

Multiply footprint length by width.
Apply a pitch factor from the 12-inch roof run and pitch rise.
Add waste and divide by 100 square feet per roofing square.

How to use the roofing calculator

Enter the simple roof footprint length and width, pitch rise per 12, and waste percent.
Press Estimate roofing to see roof area, squares, and shingle bundles.
Use the output for rough planning before contractor measurement.
Complex roofs and product coverage can change material needs.

Common uses

Estimate roof squares for a simple footprint.

Adjust for roof pitch and waste.

Estimate shingle bundles at 3 bundles per square.

Prepare a rough number before contractor measurement.

Examples

Simple roof 40 ft x 30 ft, 6/12 pitch, 10% waste

Roof squares and bundles

Low pitch 30 ft x 24 ft, 3/12 pitch

Pitch-adjusted area

Higher waste 48 ft x 32 ft, 8/12 pitch, 15% waste

Roofing material estimate

Frequently asked questions

Plain-language answers about when to use the tool, what it does with your inputs, what to double-check, and how privacy works.

When should I use the Roofing Calculator?

Use it when your task matches one of these common needs: Estimate roof squares for a simple footprint. Adjust for roof pitch and waste. It works best when you already know the values, dates, units, or settings the page asks for.

What is the Roofing Calculator doing with my inputs?

In plain language: The calculator multiplies footprint area by a pitch factor, adds waste, divides by 100 square feet per roofing square, and estimates 3 bundles per square. The examples on the page are there so you can compare your inputs with a filled-out calculation before copying the answer.

What should I double-check before trusting the answer?

Complex roofs, valleys, hips, dormers, openings, product coverage, and local installation practices can change material needs. Also check that you used the right unit, date, scale, or mode because small input changes can change the result.

Does the site save what I enter?

No. The calculator runs in your browser tab. Your recent answers stay only on the page while you use it, and they are not sent to a server.