Concrete Patio Slope Calculator

Calculate the patio fall, slope percentage, drop per foot, and slope ratio for proper drainage away from the high side.

Measurement inputs

Live calculation

Project name Used in saved report.

Unit system Switches starter units only.

Patio run / drainage distance

Distance from high side to low side.

Patio width

Used for preview and area only.

Slope input type Choose how you want to enter slope.

Patio surface note Used as a note in report.

Recommended slope Common drainage slope for outdoor concrete patios.

Equivalent Same as about 1:48 slope ratio.

Slope percent Example: 2 means 2% slope.

Drop per foot

Example: 0.25 in/ft is a 1/4 inch fall per foot.

Slope ratio

Example: 48 means 1 unit down for every 48 units forward.

Known total drop

Total fall from high side to low side.

High side elevation

Use any project datum.

Low side elevation

Low side should be lower than high side.

Enter valid measurements to calculate the patio slope.

Rounded estimates

Total fall / drop

Calculated from the selected patio run and slope input.

–

This calculator gives a slope estimate for planning. Confirm final grades with your contractor, engineer, or local code before pouring concrete.

Shown in report

Total drop = Run × Slope

All measurements are converted to feet before calculation.