Pro calculator
Gutter Calculator
Estimate gutter length, downspouts and end caps.
How the gutter calculator works
Gutter length equals the roof perimeter carrying water. Add one downspout for every ~35 linear feet, plus two end caps and one connector per corner.
Frequently asked questions
How many downspouts do I need?
One per ~35 ft of gutter is a common rule; heavy-rain regions or steep roofs may need one per 20 ft.
What size gutter for a house?
5 in K-style is standard residential; 6 in is used for large or steep roofs and areas with heavy rainfall.
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