Percent Slope Calculator

How do I calculate percent slope?

in
ft

Your slope is

10percent

Steeper than the 8.33% (1:12) maximum running slope in the ADA standards. For a ramp, confirm your design against local code.

10 ft run12 in10% slope5.7° · 1 in 10, drawn true to slope
Degrees5.7°
Ratio1:10
Rise per foot1.2 in

Enter rise and run to get slope as a percent, degrees and a ratio, drawn to scale.

How it works

Percent slope = rise ÷ run × 100, using the same units for both. Degrees = the arctangent of rise ÷ run.

Before you order

  • Use a string line and line level to measure rise over a long run.
  • Ramps for wheelchair use have a maximum running slope of 1:12, or 8.33%, under ADA standards.
  • A 100% slope is 45 degrees, which is a very common point of confusion.

Common questions

How do I convert percent slope to degrees?

Take the arctangent of the slope divided by 100.

How much fall does 1% slope mean?

About 1/8 inch per foot, or 1 inch over 8 feet.