Gutter Size Calculator
Determine the correct gutter size for your roof
How to use this calculator
The Master Roofer here—follow these steps to get a solid estimate:
- Enter roof area in square feet (use Square Footage Calculator if needed).
- Select average rainfall: light, moderate, heavy, or extreme.
- Click Calculate to see recommended gutter size and downspout count.
Heavy rainfall areas may need larger gutters or more downspouts.