Percent Grade Calculator

What Is Percent Grade?

The formula: Grade % = (Rise ÷ Run) × 100. A 6% grade means the road rises 6 feet for every 100 feet of horizontal distance. It's that simple.

On the job site: Grade stakes show the cut or fill amount from existing ground to design grade. The grade itself (slope of the road or ditch) is usually shown on the plans. Common grades you'll see:

• 0.5% – 2% — Parking lots, flat roads, minimum for drainage
• 3% – 6% — Typical highway grades, comfortable for trucks
• 8% – 10% — Maximum for loaded haul roads; trucks struggle above this
• 10% – 15% — Steep access roads; requires low-range gearing
• >15% — Extreme grades; specialized equipment only

Reading it off a grade stake: The stake typically shows the station, the offset, and the cut (C) or fill (F) amount in feet and tenths. The grade percentage comes from the plans. Set your laser or grade rod to the design elevation and check against the stake shot.

Negative grade: A negative grade value (e.g., -3%) means the road is descending in the direction of travel. This calculator handles both positive and negative rise values.