Math Calculator
Slope Percentage Calculator
Calculate slope percentage, slope ratio, angle in degrees, decimal slope, and slope length from rise and run, two points, percent grade, or angle.
Example: 5 rise ÷ 100 run × 100 = 5% slope
Calculate slope percentage
Choose the input mode, enter your values, and the calculator will show percent grade, angle, slope ratio, decimal slope, and slope length.
Visual slope chart
A 5.00% slope rises 5 units for every 100 units of horizontal run.
Step-by-step calculation
Slope % = 5 ÷ 100 × 100 = 5.00%
How to calculate slope percentage
Slope percentage tells you how much a surface rises or falls over a horizontal distance. It is often used for roads, ramps, driveways, roofs, drainage, hiking trails, and geometry problems.
Formula: slope percentage = rise ÷ run × 100
Example: if rise = 8 and run = 100, then slope percentage = 8 ÷ 100 × 100 = 8%.
Since this is a percentage-based calculation, you may also find CalcMora’s percentage calculator useful for general percent problems. For comparing how much a value has changed, try the percentage increase calculator.
Slope percentage examples
| Input | Slope % | Angle | Ratio |
|---|---|---|---|
| Rise 5, Run 100 | 5% | 2.86° | 1 in 20 |
| Rise 10, Run 100 | 10% | 5.71° | 1 in 10 |
| Rise 25, Run 100 | 25% | 14.04° | 1 in 4 |
| Rise 50, Run 100 | 50% | 26.57° | 1 in 2 |
| Rise 100, Run 100 | 100% | 45° | 1 in 1 |
Slope percentage, angle, and ratio explained
A slope can be written in several ways. A percentage grade shows rise compared with every 100 units of run. A slope angle shows the incline in degrees. A ratio, such as 1 in 20, means 1 unit of rise for every 20 units of run.
For example, a 1 in 20 slope equals 5%, because 1 ÷ 20 × 100 = 5. A 100% slope does not mean vertical; it means rise and run are equal, which creates a 45 degree angle.
Where this calculator is useful
Roads and driveways
Estimate road grade, driveway steepness, hill incline, and vehicle access slope.
Ramps and accessibility
Compare rise and run to understand how steep a ramp or walkway is.
Math and geometry
Convert between slope, percent grade, angle, ratio, and two-point coordinate slope.
Frequently asked questions
How do you calculate slope percentage?
Divide rise by run, then multiply by 100. For example, if rise is 5 and run is 100, slope percentage is 5%.
What is a 10% slope?
A 10% slope means the surface rises or falls 10 units for every 100 units of horizontal distance.
Is slope percentage the same as angle?
No. Slope percentage compares rise to run, while angle is measured in degrees. A 100% slope equals a 45 degree angle because rise and run are equal.
How do I calculate slope percentage from two points?
Find rise by subtracting y1 from y2, find run by subtracting x1 from x2, then divide rise by run and multiply by 100.
What does 1 in 20 slope mean?
A 1 in 20 slope means 1 unit of rise for every 20 units of run. As a percentage, it is 1 divided by 20 times 100, which equals 5%.