1 to 25 is 4%, you can get this by using 1 to divide 0.04, so you can get 25.

# What Is A 4% Slope. How Do You Find The Length And Drop In Relation To A % Slope Given?They Say I Have A 4% Slope On My Patio.

A 4% slope = .5" drop for every 12 inches. That means for every 24 inches the drop in height is one inch. One divided by 24= .041666, rounded up to 4%.