Roof Area and Shingles Calculator
Fill in the values and the answer updates as you type.
How the Roof Area and Shingles Calculator works
Roof area = footprint (including overhang) × slope factor, where slope factor = √(1 + (pitch ÷ 12)²). A 6/12 pitch has a factor of 1.118. One roofing square covers 100 sq ft, and most shingles come 3 bundles to the square. This suits simple gable and hip roofs; complex roofs need a professional measure.
Inputs and results
The Roof Area and Shingles Calculator takes 4 inputs and gives 5 results.
What you enter
- Building length (ft) — starts at 40.
- Building width (ft) — starts at 28.
- Roof pitch (rise per 12 in. run) — starts at 6.
- Overhang on each side (ft) — starts at 1.
What you get
- Roof surface area (sq ft)
- Roofing squares
- Shingle bundles (3 per square, +10%)
- Slope factor
- Roof angle (degrees)
Example: Roof Area and Shingles Calculator with the starting values
With building length 40 ft, building width 28 ft, roof pitch (rise per 12 in. run) 6 and overhang on each side 1 ft, the calculator returns:
| Roof surface area (sq ft) | 1,409 |
|---|---|
| Roofing squares | 14.1 |
| Shingle bundles (3 per square, +10%) | 47 |
| Slope factor | 1.118 |
| Roof angle (degrees) | 26.6 |
Change any value above and the results update straight away.
Roof Area and Shingles Calculator FAQ
How do I use the Roof Area and Shingles Calculator?
Enter building length, building width, roof pitch (rise per 12 in. run) and overhang on each side in the fields, then read roof surface area (sq ft), roofing squares, shingle bundles (3 per square, +10%) and slope factor in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Roof Area and Shingles Calculator calculate?
Estimate roof surface area, squares, and shingle bundles from pitch. It returns roof surface area (sq ft), roofing squares, shingle bundles (3 per square, +10%) and slope factor from the 4 values you provide.
What values does the Roof Area and Shingles Calculator start with?
It opens with building length 40 ft, building width 28 ft, roof pitch (rise per 12 in. run) 6 and overhang on each side 1 ft so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Roof Area and Shingles Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Roof Area and Shingles Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.