Gutter Size Calculator
Size gutters for roof drainage area
sq ft
in/hr
Formula
GPM = Area × Rainfall × 0.0104
Converts sq ft and in/hr to gallons per minute.
Examples
1500sqft, 4in/hr
5-inch gutters with 2 downspouts.
Frequently Asked Questions
About Gutter Size
Size gutters and downspouts for roof drainage.