Drainage Slope Calculator — Calculate Proper Drainage Gradients

Drainage Slope Calculator

Calculate drainage slope percentages and gradients for pipes, gutters, and landscaping. Determine proper slope for efficient water drainage and prevent pooling.

Step 1: Drainage Dimensions

10 ft
0.5 in

Understanding Drainage Slopes

Proper drainage slopes typically range from 0.125″ to 1″ per foot. Landscape drainage requires at least 0.25″ per foot, while sewer pipes need 0.125″ per foot minimum.

Step 2: Units & Options

About Drainage Slopes

Proper drainage slope prevents water pooling, foundation damage, and erosion. Insufficient slope causes standing water, while excessive slope may cause erosion or pipe separation.

Drainage Slope Results

Summary
Drainage Comparison
Visualization

Slope Percentage

0.42%
0.5″ drop over 10 feet
Ratio Format
1:240
Inches per Foot
0.5 in/ft
Angle
0.24°
Total Drop
0.5 in

Drainage Type Slope Requirements

Drainage Type Minimum Slope Recommended Slope Slope Percentage

Slope Visualization

Slope Calculation Formula

Slope Percentage = (Drop ÷ Run) × 100

To calculate slope percentage: Divide the vertical drop by the horizontal run, then multiply by 100 to get percentage. For inches per foot: Drop per foot = Total Drop ÷ Run Length.

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