Slope and Grade Calculator

Slope describes how steeply a surface rises over a horizontal distance, and there are three ways people write it down. The rise is the vertical change, the run is the horizontal distance, and everything follows from their ratio. Grade percent is `rise ÷ run × 100`, so `1 ft` of rise over `4 ft` of run is a `25%` grade. The angle in degrees is the arctangent of that same ratio, which here is about `14°`. The rise-to-run ratio just states the two numbers side by side, `1 : 4`.

Enter the rise and run in whatever matching unit you have — feet, meters, or both in inches — and the calculator returns all three forms at once. Because grade, angle, and ratio are pure ratios, the answer is identical no matter which length unit you use, as long as rise and run share it. Grade percent is common for driveways, drains, and ADA ramps; degrees suit roof cuts and solar tilt; the ratio is the language of stairs and railroad track. A drain line, for reference, usually wants about a `2%` grade, or `1/4 in` of fall per foot.