Slope & Grade Calculator
From Rise and Run
Calculate slope from known rise and run distances
From Percent Grade
Given a percent grade and one distance, calculate the other
Formula
Grade % = (Rise / Run) × 100 | Angle = arctan(Rise / Run) | Slope Distance = √(Rise² + Run²)
Frequently Asked Questions
What is the minimum slope for drainage?
The minimum slope for proper surface drainage is 1-2% (1/8 to 1/4 inch per foot). Drainage pipes typically require 1-2% grade. Gutters need at least 1/16 inch per foot slope toward downspouts. Concrete patios should slope 1/8 inch per foot away from the house.
What is the maximum slope for a driveway?
Most building codes limit residential driveways to 15-25% grade depending on climate. In snow-prone areas, 10-12% is the practical maximum. ADA-accessible routes are limited to 5% running slope, and ramps to 8.33% (1:12 ratio).
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