### Calculating Slope and Common Slopes in Architecture ...

Aug 17, 2020·Calculating a Slope Gradient. Slope gradients are written as Y:X, where Y is a single unit in rise and X is the run. Both numbers must use the same units. For instance, if you travel 3 inches vertically and 3 feet (36 inches) horizontally, the slope would be 3:36 or 1:12. This is read as a "one in twelve slope."