Ramp Slope Calculator — Grade, Angle & Length
Enter the vertical rise and horizontal run of any ramp or incline — driveway, loading dock, skateboard ramp — to get the slope percentage, angle in degrees, ramp surface length, and rise-to-run ratio.
m
m
Unit
Percentage grade (rise ÷ run × 100)
- 1
Slope ratio
1 ÷ 10 = 0.1 - 2
Slope percentage
0.1 × 100 = 10
How does this calculator work?
Slope% = (rise ÷ run) × 100. Enter rise and run to also get the angle in degrees (arctan(rise/run)) and ramp surface length (√(rise² + run²)). Common standards: ≤8.33% for ADA ramps, ≤15% for driveways, ≤6% for roads without warning signs. All three measurements share the same unit.
Formula
How this is calculated
Slope is how much a surface rises vertically for each unit it travels horizontally. Enter the rise (total height gained) and run (horizontal distance) in the same unit and the calculator gives four equivalent expressions of the same steepness: percentage grade, angle in degrees, the ramp surface length (hypotenuse), and the rise-to-run ratio.
The slope percentage is rise divided by run times 100, so 1 m of rise over 10 m of run is 10%. The angle in degrees is arctan(rise/run) — 10% equals about 5.71°. The ramp surface length is the hypotenuse of the right triangle formed by rise and run: √(rise² + run²); it is always slightly longer than the horizontal run. The diagram illustrates these three sides and their relationship.
Common benchmarks: the ADA maximum for an accessible ramp is 8.33% (1:12, about 4.8°); residential driveways typically stay below 15%; public roads above 6% usually carry advisory signs; anything above 25% is difficult and hazardous when wet. Keep rise and run in the same unit — if the unit is metres, results are in metres; if inches, results are in inches.
Frequently asked questions
Slope percentage is vertical rise divided by horizontal run, multiplied by 100. A 10% grade means 1 metre of rise for every 10 metres of horizontal distance. It equals 100 × tan(angle).
Angle = arctan(slope% / 100). A 10% grade is arctan(0.10) ≈ 5.71°. A 100% slope equals exactly 45°. Use a calculator with a tan⁻¹ button or this calculator.
The ADA requires a maximum running slope of 1:12 (8.33%, about 4.8°) for accessible ramps. Gentler slopes such as 1:16 (6.25%) reduce effort and are preferred for unassisted use.
Also known as
TG we-Calculate Editorial Team. (2026). Ramp Slope Calculator — Grade, Angle & Length [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/ramp-slope-calculator
TG we-Calculate Editorial Team. "Ramp Slope Calculator — Grade, Angle & Length." TG we-Calculate. 2026. https://we-calculate.com/calculator/ramp-slope-calculator.
TG we-Calculate Editorial Team, "Ramp Slope Calculator — Grade, Angle & Length," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/ramp-slope-calculator
@misc{wecalculate_ramp_slope_calculator, title = {Ramp Slope Calculator — Grade, Angle & Length}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/ramp-slope-calculator}}, year = {2026}, note = {TG we-Calculate} }
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