DIY Cost Tools
Ramp Slope Calculator
HOME & OUTDOOR PLANNING
Calculate ramp slope, angle, and sloped length from vertical rise and horizontal run.
Use the units shown. All fields are required; absolute values cannot exceed one trillion. This is geometry only. It does not determine accessibility compliance, safe loading, surface traction, landings, handrails, or permit requirements. Verify the applicable project requirements with a qualified professional.
How to use this calculator
Replace the example inputs with your own measured values, using the units beside each field. Select Calculate, then compare results under different practical assumptions. Keep extra precision in measurements until the final answer.
Formula and explanation
Slope % = 100 × rise/run; angle = arctan(rise/run); sloped length = √(rise²+run²)
Horizontal run is the level distance beneath the ramp. The sloped walking surface is slightly longer than that horizontal distance.
Worked example
With Vertical rise (inches) = 12, Horizontal run (inches) = 144, the results are Slope (%): 8.3333333; Angle (degrees): 4.7636417; Sloped length (feet): 12.041595; Horizontal run (feet): 12.
Important limitations
This is geometry only. It does not determine accessibility compliance, safe loading, surface traction, landings, handrails, or permit requirements. Verify the applicable project requirements with a qualified professional.
These are planning estimates. Confirm actual measurements, product instructions, site conditions, and any applicable project requirements before purchase or installation.
Frequently asked questions
Is ramp length the same as run?
No. Run is horizontal; ramp length follows the incline.
Can this approve an accessible ramp?
No. Accessibility requirements include more than slope and depend on the applicable rules and project.
Can I mix measurement units?
No. Convert values to the units shown beside the fields first. The result labels identify the output units.
What happens when inputs are invalid?
Blank, negative where disallowed, nonfinite, or out-of-range values clear the old results and show an instruction.
Review notes
Reviewed October 1, 2026. Default examples were checked independently against the displayed equations and conversion factors. Page-script tests covered blank, negative, nonfinite, and excessive inputs. Calculations run locally in your browser.