Making the Grade

Can someone explain the calculation for gradient percent? I figure it has something to do with the length of the slope vs the rise but do not know the calculation.

I was riding up a hill today and someone suggested it was 7%. Just guessing I'd say the road rose about 60-70 feet over a 180-200 foot stretch. It was short but steep, everyone was out of their seat. I have a hard time believeing it was only 7%. Especially when I think about the Giro and they were climbing a 27% grade. If my 7% gradient was truly 7% then pro cyclists can climb walls.

the percentage is rise over run. rise 7 feet for every 100 feet

7/100 = 0.07 or 7%

a vertical wall would have a grade of infinity

45 degree slope is 100% grade

M2 thanks for the info....