Ramp geometry
Ramp Rise-and-Run Calculator
Calculate the missing ramp dimension from rise or run, then see the resulting surface length, slope angle and grade percentage in one view.
Enter known geometry
The optional grade mode is a geometry solver. Accessibility and building requirements vary by application and jurisdiction, so use the applicable project criteria separately.
Enter ramp rise/run or use grade mode.
Ramp geometry
Surface length——
—Rise
—Run
—Grade
—Angle
—
Ramp calculation method
Grade % = rise ÷ run × 100
Angle = atan(rise ÷ run)
Surface length = √(rise² + run²)
Angle = atan(rise ÷ run)
Surface length = √(rise² + run²)
Example
A 0.75 m rise over a 9 m run gives an 8.33% grade. The surface length is approximately 9.03 m and the slope angle is about 4.76°.
Why percentage and angle both matter
Grade percentage is common for project dimensions, while angle describes the geometric inclination. They describe the same relationship in different forms.
Frequently Asked Questions
Can rise be zero?
Yes, representing a level run, although the entered dimensions must still define a valid geometry.
Can grade be negative?
This calculator is intended for an upward ramp, so negative grade is rejected.
Does surface length equal horizontal run?
No. A sloped surface is slightly longer than its horizontal projection.