Forklift Ramp Gradeability Calculator
Convert a ramp’s rise and run into a grade and angle, and check it against a typical forklift gradeability limit.
Ramp grade
Grade % = rise ÷ run × 100; angle = arctangent of that ratio. Typical counterbalance forklifts are limited to roughly 15% gradeability unladen and much less when loaded — check your truck’s rating. Drive straight up and down a grade with the load upgrade, and never turn, angle across, or raise the load on a slope.
Grade, angle, and the load on a slope
A ramp’s steepness can be written two ways — as a grade percentage or an angle in degrees — and it helps to have both, because drawings and truck specifications don’t always agree on which to use. Grade is rise over run; the angle is its arctangent.
The number only tells half the story on a forklift. A slope reduces traction and braking and raises the tipping risk, all the more with a load aboard, which is why gradeability limits exist and why you keep the load upgrade, travel straight up and down, and never turn on a ramp.
Frequently Asked Questions
How do you calculate a ramp's grade?
Grade is the vertical rise divided by the horizontal run, expressed as a percentage: a 1 m rise over a 10 m run is a 10% grade. The incline angle is the arctangent of the same ratio — about 5.7° for that 10% ramp. Enter rise and run in any consistent unit, or type a grade percentage directly.
What grade can a forklift handle?
It depends on the truck, but typical counterbalance forklifts are limited to roughly a 15% gradeability unladen, and considerably less when carrying a load. The calculator defaults to a 15% limit for a quick check, but the authoritative figure is your specific truck's rated gradeability — check its specifications.
Why is a loaded forklift more restricted on a ramp?
A load raises the combined center of gravity and shifts stability, and on a slope gravity adds a component pulling the machine downhill. That reduces available traction and braking and increases the risk of tipping or the load shifting. Rated gradeability figures for loaded travel are therefore much lower than unladen ones.
How should a forklift travel on a grade?
The long-standing rule is to keep the load pointed upgrade — drive forward going up and in reverse coming down when carrying a load, so the load stays on the uphill side. Travel straight up and down the slope, never turn on a ramp, don't angle or drive across a grade, and keep the forks and load low and tilted back. Follow your site's traffic rules and your truck's operator manual.
Is grade the same as the angle in degrees?
No, they measure the same slope differently. Grade is a percentage (rise over run × 100), while the angle is in degrees. They only match at very shallow slopes; a 100% grade, for instance, is a 45° angle, not 100°. This tool shows both so you can match whichever your ramp drawing or truck spec uses.
Estimates for planning — not professional safety, OSHA, or operator-certification advice. Follow your truck’s rated gradeability and site traffic rules, and get trained and certified before operating on any grade.