Elevation Grade Calculator

Elevation grade, also known as slope, is the steepness or degree of inclination of a surface. It measures how much vertical rise occurs over a given horizontal distance, commonly expressed as a percentage, angle in degrees, or ratio.

Grade percentage is calculated by dividing the rise by the run and multiplying by 100. The formula is: Grade % = (Rise ÷ Run) × 100. For example, if you have a 5-foot rise over a 100-foot run, the grade is 5%.

Slope as a percentage is the ratio of rise to run multiplied by 100, while slope as an angle is measured in degrees from the horizontal. A 100% grade equals 45 degrees. Percentages are more commonly used in construction and road work.

Rise is the vertical distance between two points, measured straight up or down. Run is the horizontal distance between the same two points, measured along the ground. Use a level, measuring tape, and stakes to accurately measure both distances.

A 1 in 20 slope means 1 unit of rise for every 20 units of run, which equals 5% grade. This is calculated as (1 ÷ 20) × 100 = 5%. This slope is commonly used for wheelchair ramps and drainage.

Elevation grade is crucial for proper drainage, structural stability, accessibility compliance, and material calculations. It helps determine excavation needs, foundation requirements, and ensures water flows away from buildings properly.

A 100% slope corresponds to 45 degrees. This occurs when the rise equals the run, creating a 1:1 ratio. At this angle, for every unit you go horizontally, you also go up one unit vertically.

Most roads have grades between 0-6%, with 8-12% considered steep. The steepest public roads can reach 20-37% grade. Highway design typically limits grades to 6-8% for safety and vehicle performance reasons.