Percent Grade Calculator
Find site or road grade from elevation change and horizontal distance. Results include percent grade, 1:X ratio, and fall per 100 feet.
Enter your values, then press Calculate.
How to calculate
Enter the elevation difference (rise) and the horizontal run. Field shots are often in feet of rise over a taped distance. The calculator converts both values to feet, then reports percent, ratio, and fall per 100 feet.
Formula
Grade = rise ÷ run. Percent grade = grade × 100. Ratio 1:X uses X = run ÷ rise. Feet per 100 feet equals the percent grade when rise and run use the same length unit.
Common use cases
- Driveway and parking grade checks
- Swale and ditch slopes
- ADA and plan-minimum grade reviews
- Converting 1/4 in per foot to percent
Worked example
Example: 4 feet in 100 feet is 4 percent
1. Decimal slope
4 ft ÷ 100 ft = 0.04 ft/ft
2. Percent grade
0.04 × 100 = 4 %
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FAQ
What is a 2% grade?
A 2% grade rises or falls 2 feet in 100 feet, or 1/4 inch per foot.
How is this different from pipe slope?
The math is the same. This tool is framed for site and road grade. Use the pipe slope calculator when you need inches per foot for utilities.
Disclaimer
These calculators are estimating tools for planning and field checks. They are not a substitute for approved plans, specifications, licensed professional engineering, or governing standards. Confirm densities, waste factors, and yields with your supplier and project documents.