Roof Pitch Multiplier Calculator
Instantly calculate the exact area and number of squares needed for a pitched roof based on its footprint.
How to use this calculator
When you are quoting a roofing job, measuring the exact area of the roof from the ground can be difficult. However, finding the footprint of the house (the area of the flat ceiling underneath the roof) is usually much easier.
Because the roof is angled, its total area is greater than the footprint. To find the true area, you multiply the footprint by the pitch multiplier.
The Formula
The multiplier is derived from the Pythagorean theorem:
Multiplier = √((Pitch ÷ 12)² + 1)
Once you have the total area, you divide by 100 to find the total number of squares (since 1 roofing square = 100 sq ft). Remember to add an extra 10% to 15% to your final square count to account for waste!
Want to stop guessing entirely?
Calculators are great, but showing the homeowner exactly what their new roof will look like is better. CurbClose uses AI to visualize your exact shingles on their home instantly.
See It In Action