Gutter Rain Calculator
Gutter Rain
Estimate rainwater volume collected from your roof gutters.
Formula
Gallons = Roof Area x Rainfall x 0.623 x Efficiency
Frequently Asked Questions
How much rain can a roof collect?
A 2,000 sq ft roof collects about 1,246 gallons per inch of rain.
What affects rainwater collection efficiency?
Roof material, slope, gutter condition, and debris all affect efficiency.