Gutter Calculator
Calculate gutter size, downspout requirements, and gutter capacity for your roof. Determine correct gutter dimensions based on roof area and rainfall intensity.
Step 1: Roof Dimensions
Roof Area: 1,200 sq ft
Understanding Roof Area
Effective roof area = (Length × Width) × Pitch Factor. Steeper roofs collect more water per square foot. This calculator uses the adjusted roof area for accurate gutter sizing.
Step 2: Gutter Configuration
Gutter Capacity Guidelines
5-inch gutter: Handles up to 5,520 sq ft roof area
6-inch gutter: Handles up to 7,960 sq ft roof area
Add downspouts every 30-40 ft. 4-inch downspouts handle 600 sq ft each.
Gutter Calculation Results
Recommended Gutter System
Gutter Capacity Analysis
Your selected gutter size is adequate for your roof area.
Materials Needed
| Material | Quantity | Purpose | Estimated Cost |
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Installation Notes
• Gutter sections typically come in 10ft lengths
• Add 10% extra for waste and cuts
• Include end caps, inside/outside corners, and fascia brackets
• Downspout elbows needed for each direction change
Gutter Installation Guidelines
Slope Requirements
Minimum slope: 1/4 inch per 10 feet toward downspouts
Maximum slope: 1/2 inch per 10 feet
Check slope: Use a level and measure from the roof edge, not the fascia.
Downspout Placement
Spacing: Place downspouts every 30-40 feet maximum
Capacity: 4-inch downspout handles 600 sq ft of roof area
Location: Place at corners or areas with natural drainage
Material Considerations
Vinyl: Easy DIY, expands/contracts, limited colors
Aluminum: Lightweight, rust-resistant, painted finish
Steel: Durable, may rust, heavier
Copper: Premium, develops patina, expensive
Maintenance Tips
• Clean gutters twice yearly (spring and fall)
• Check for leaks at joints and seams
• Ensure downspouts extend 5-10 feet from foundation
• Consider gutter guards to reduce cleaning frequency
Need Professional Gutter Installation?
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