FullCalculator

Gutter Size Calculator

Gutter Size Selection

Calculate the right gutter size based on roof drainage area and rainfall

Gutter Materials & Cost

Estimate gutter materials and installation cost

Formula

Drainage Area = Roof Length × Width × Pitch Factor | Adjusted Area = Drainage Area × Rainfall Intensity | Downspouts = Adjusted Area / Gutter Capacity

Frequently Asked Questions

What size gutters do I need?
Most homes use 5" K-style gutters. Upgrade to 6" K-style if your roof area exceeds 5,500 sq ft per gutter run, you live in a heavy rainfall area (5+ in/hr), or your roof has a steep pitch (8/12 or steeper).
How often should gutters be cleaned?
Clean gutters at least twice a year - in late fall (after leaves drop) and late spring. Homes near pine trees or with heavy tree coverage may need quarterly cleaning. Gutter guards can reduce cleaning frequency.

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