Oakland Yellowjackets Bicycling Club

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Home Rides Bay Area Climbs Understanding Grade

Understanding Grade

Most of us find that climbing up a 500-foot hill which is steep takes more out of us than a 500-foot hill which is gentle (think Pinehurst vs. Redwood Rd). We can express the steepness of any hill by determining it's grade which is a measurement of the angle of inclination expressed at a percentage.

To calculate the grade of a section of road, simply divide the rise (vertical_climb) by the run (horizontal_distance).

grade % = vertical_climb / horizontal_distance * 100

Both vertical_climb and horizontal_distance should both converted to the same measurement units (usually feet). So if a hill goes up 500 feet in one mile, then we can first convert the mile to 5280 feet -- so the grade is then 9.46% (500 / 5280 * 100).


What does this "grade" number mean?

  • 0% grade is exactly flat (and a negative grade, less then zero, is downhill).
  • 2-3% grade does not seem very steep, but it's enough to substantially reduce forward speed, and for most riders it will absorb more than half their power output.
  • 5-7% grade is enough to cut speed to well under half, and absorb 75-85% of a rider's power output (leaving less than 15-25% to fight air resistance and rolling friction).
  • 9-11% grade, and anyone who is not a great shape and frequent rider is off the bike walking&,dash;and anyone who is not a racer is reaching for all the extra power they've got.
  • 20+% grade, and you're out of the saddle sucking wind or weaving methodically up the road.

Note: the term grade should not be confused in any way with angle. They are two very different things. For example, a flat surface can be referred to as a 0% grade or a 180-degree angle: there is no change in height as the road continues. (There is no rise over the run.) A 100% grade would be equivalent to a 45-degree angle or, in other words, the rise would be equal to the run.

Grade Calculator

Vertical Change Percentage
Vertical Change (Rise) Feet
Horizontal Distance (Run) Miles
% Grade Percent

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What is Grade?

Want to know more about grade? How is calculated and what it means? Read "Understanding Grade".

Have a look at the Tour de France climb ratings if you see another way to rate climbs.