Calculate roof area, roofing squares, roof pitch, roof shingles, and estimated roofing costs quickly and easily.
Use this roofing calculator to estimate the surface area of a rectangular roof based on its length, width, and roof pitch. You can also add a waste percentage and an estimated price per roofing square.
Enter the roof rise and run to calculate the roof pitch, roof angle, and slope multiplier.
Estimate how many roofing shingle bundles are needed based on your roof area and the coverage of each bundle.
Calculate roof area, roofing squares, material waste, and estimated cost.
Calculate roof pitch, roof angle, and slope multiplier from rise and run.
Estimate the number of roofing shingle bundles needed for your project.
To calculate roof area, start with the building or roof section's length and width. Multiply the length by the width to find the basic horizontal footprint.
Because a roof is sloped, the actual roof surface is larger than the horizontal footprint. Roof pitch can be used to determine a slope multiplier and estimate the sloped roof area.
The calculator above uses the roof pitch to determine the slope multiplier automatically. It can then add a waste percentage to estimate the amount of roofing material needed.
One roofing square equals 100 square feet of roof area. Roofing contractors commonly use roofing squares when estimating shingles and other roofing materials.
Roof pitch describes how steep a roof is. A common way to express roof pitch is rise over a 12-inch run.
For example, a 6/12 roof pitch means the roof rises 6 inches for every 12 inches of horizontal run.
Roof pitch is important when estimating roof surface area because a steeper roof has more surface area than the same horizontal footprint with a lower pitch.
| Pitch | Rise per 12 in. Run | Approx. Angle |
|---|---|---|
| 3/12 | 3 inches | 14.04° |
| 4/12 | 4 inches | 18.43° |
| 6/12 | 6 inches | 26.57° |
| 8/12 | 8 inches | 33.69° |
| 10/12 | 10 inches | 39.81° |
| 12/12 | 12 inches | 45.00° |
The number of shingle bundles required depends on the total roof area, the amount of waste, and the coverage provided by the specific shingle product.
Enter the roof area and the coverage per bundle into the shingle calculator above to estimate the number of bundles. Because products vary, always use the coverage information provided by the shingle manufacturer.
Roofing projects usually require extra material because of cutting, overlapping, damaged materials, installation waste, and the shape of the roof.
A waste percentage can therefore be added to the calculated roof area. The appropriate amount depends on the roof design, material, installation method, and project conditions.
RoofCalcNow provides estimates based on the information entered by the user. The main roof calculator is designed for a simple rectangular roof calculation using length, width, and pitch.
Complex roofs may contain multiple roof sections, valleys, dormers, skylights, chimneys, overhangs, or other features. For these roofs, each section should be measured separately and the results combined. For construction or purchasing decisions, verify measurements and material requirements with a qualified roofing professional or the product manufacturer.
One roofing square is equal to 100 square feet.
Start with the horizontal length and width of the roof section, then account for the roof slope. For a simple rectangular roof, the slope multiplier can be used to estimate the actual roof surface area.
The number of bundles can vary depending on the shingle product and its coverage. Check the manufacturer's packaging for the exact coverage.
Many estimates use around 10% waste, although the actual amount depends on the roof design, materials, and installation method.
A 6/12 roof pitch means the roof rises 6 inches for every 12 inches of horizontal run. The corresponding roof angle is approximately 26.57 degrees.
Yes. The calculators are designed to work on desktop, tablet, and mobile devices.
The calculator is intended as an estimate for simple rectangular roof sections. Complex roof designs should be divided into individual sections and measured separately.