Grade (Slope) Calculator

About this calculator

Grade expresses the steepness of a slope as a percentage: grade % = (rise / run) × 100, the vertical rise divided by the horizontal run; this calculator also converts that into the equivalent angle via arctan(rise/run), since percent grade and degrees are easy to confuse (a 100% grade is a 45° angle, not vertical).

Civil engineers use grade limits to design roads and highways safe for trucks and buses, railway engineers keep gradients well under road standards because trains have far less traction, cyclists use grade percentages to rate climb difficulty (like Strava segment stats), and accessibility planners must keep wheelchair ramps at or below a 1:12 ratio (about 8.3%) under ADA guidelines. Enter rise and run to get both the percentage and the angle.