Ramp Calculator

1:12 — for every 1 inch of vertical rise, the ramp needs at least 12 inches of horizontal run. That's about an 8.3% slope, the steepest allowed for new unassisted construction.

Ramp length is the hypotenuse of the rise and run: length = √(rise² + run²). Run is found by multiplying the rise by the slope ratio (e.g. rise × 12 for a 1:12 slope).

The ADA caps a single ramp run at 30 feet of horizontal length. Longer rises need to be split into multiple ramp sections joined by flat landings at least 5 feet long.

Handrails are required on both sides of any ramp with a rise greater than 6 inches under the ADA.