Gutter Size Calculator
Calculate the right gutter size for your roof. Based on roof area, pitch, and rainfall intensity for proper drainage.
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Gutter Sizing Calculation
Adjusted Area = Roof Area × Pitch Factor × Rainfall Factor
Calculate effective drainage area
Gutter Size = Based on Adjusted Area capacity
Select gutter for required flow
Gutter sizing considers the effective drainage area - not just roof size, but how quickly water runs off. Steeper roofs and higher rainfall areas need larger gutters.
K-Style gutters handle the most water for their size due to their flat back and decorative front. Half-round drains well but has lower capacity. Box gutters are for commercial applications with very high volumes.
Downspouts must be properly sized and spaced. Too few downspouts causes overflow during heavy rain.
Reference: Sheet Metal and Air Conditioning Contractors' National Association (SMACNA) guidelines