How to Size Gutters
Adjusted Area = Roof Area × Pitch Factor
Max Flow = Adjusted Area × Rainfall Rate ÷ 96.23
5" K-Style: handles ~5,520 sq ft @ 1 in/hr
6" K-Style: handles ~7,960 sq ft @ 1 in/hr
Gutter Size Guide
- 5" K-Style: Standard for most residential homes. Handles up to 5,520 sq ft per section at 1"/hr rainfall.
- 6" K-Style: For larger roofs, steep pitches, or heavy rainfall areas. 44% more capacity than 5".
- Half-Round: Decorative style with ~30% less capacity than K-style of the same size. Common on historic homes.
- Downspouts: Each 2"×3" downspout drains up to 600 sq ft; each 3"×4" drains up to 1,200 sq ft.