Gutter Slope Calculator
Calculate the proper slope (pitch) for your rain gutters. Get the exact drop needed for efficient water drainage and prevent pooling, overflow, and foundation damage.
📏 Gutter Measurements
💧 Water flows to one end
📊 Slope Results
Total Drop Required
0.00"
Visual Slope Diagram
📋 Quick Reference: Gutter Slope by Length
Total drop required for common gutter lengths
| Gutter Length | Standard 1/4" per 10ft | Maximum 1/2" per 10ft |
|---|---|---|
| 10 ft | 0.25" | 0.50" |
| 20 ft | 0.50" | 1.00" |
| 30 ft | 0.75" | 1.50" |
| 40 ft | 1.00" | 2.00" |
| 50 ft | 1.25" | 2.50" |
| 60 ft | 1.50" | 3.00" |
| 80 ft | 2.00" | 4.00" |
| 100 ft | 2.50" | 5.00" |
Frequently Asked Questions
To calculate gutter slope, use the formula: Total Drop = (Gutter Length ÷ 10) × Slope Rate. The standard slope rate is 1/4 inch per 10 feet of gutter. For example, a 30-foot gutter needs: (30 ÷ 10) × 0.25 = 0.75 inches of total drop from the high end to the downspout.
For a 50-foot gutter run using the standard 1/4 inch per 10 feet slope: (50 ÷ 10) × 0.25 = 1.25 inches total drop. If using the maximum 1/2 inch per 10 feet slope for heavy rainfall areas: (50 ÷ 10) × 0.50 = 2.50 inches total drop.
Gutters should drop between 1/4 inch (0.25") to 1/2 inch (0.50") for every 10 feet of length. The standard recommendation is 1/4 inch per 10 feet for most applications. Use 1/2 inch per 10 feet in areas with heavy rainfall or if you want faster drainage.
The minimum fall (slope) for gutters is 1/4 inch per 10 feet (approximately 0.2% grade or 0.12 degrees). This minimum ensures water flows toward the downspout rather than pooling in the gutter. Less slope can cause standing water, debris buildup, and potential overflow during rain.
The standard gutter slope of 1/4 inch per 10 feet equals approximately 0.12 degrees (or 0.21% grade). The maximum recommended slope of 1/2 inch per 10 feet equals approximately 0.24 degrees (or 0.42% grade). These slight angles are barely visible but essential for proper drainage.
Use a single downspout at one end for gutter runs up to 40 feet. For runs longer than 40 feet, install downspouts at both ends and slope the gutter from the center toward each end. This prevents excessive drop at one end and ensures efficient drainage for longer roof lines.
⚠️ Disclaimer: This calculator provides general guidelines for gutter slope. Actual requirements may vary based on local building codes, rainfall intensity, roof design, and gutter type. Consult a professional for complex installations.