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Patio Slope Calculator

Estimate the total drop needed across a patio from run length and a drainage-slope assumption.

Updated April 16, 2026
Free online tool
Planning and research use

Why this page exists

Drainage planning gets easier when patio run length and slope are turned into one required-drop figure instead of being worked out in the field by hand. This calculator helps visitors estimate total patio drop from run length and either a drop-per-foot or slope-percentage input.

Interactive tool

Run the estimate

Enter your numbers and read the result first, then use the sections below to understand what affects the outcome.

Calculator

Patio slope calculator

Estimate total drop needed across a patio from run length and either a slope-per-foot or slope-percentage assumption.

Result

3.50 in drop

Estimated total patio drop based on the run length and the drainage slope basis entered.

Total required drop3.50 in

Slope used0.250 in/ft

Run length used14.0 ft

Equivalent drop in feet0.292 ft

14.0 feet of patio run at 0.250 inches per foot creates a total drop near 3.50 inches.
That same patio slope is about 2.08% when the vertical drop is compared with the full horizontal run.
Use the output as a simple field-planning guide, then confirm the actual drainage path, finished elevations, and base preparation before building.

This is a field-planning estimate only. Final patio drainage still depends on layout, surface tolerances, base prep, and site-specific conditions.

Planning note

Last updated April 16, 2026. Use this tool to compare scenarios and plan ahead, then confirm important details with the lender, employer, insurer, contractor, or other qualified provider involved in the final decision.

How it works

What the calculator is doing

Choose whether you want to work from drop per foot or slope percentage.

Enter the patio run length and the matching slope input.

The calculator estimates total required drop and shows the slope basis used.

Understanding your result

This is a simple drainage-planning estimate. Base preparation, finished elevations, and site conditions can still affect the real patio layout.

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Examples

Ways people use this tool

Example scenarios help turn a quick estimate into a more useful comparison or planning step.

Turn a standard drainage slope into total drop

A run-length-based drop estimate can make layout stakes and elevation planning easier.

Convert percentage slope into field-friendly drop

Using the percentage mode can help when the slope is already specified mathematically but needs to be applied on site.

Use it with paver and slope tools

Patio slope planning often fits naturally beside paver, base, and general slope calculations.

FAQ

Common questions

How is patio slope estimated here?

The calculator uses the patio run length together with either a drop-per-foot input or a slope-percentage input to estimate the total drop across the patio.

Why show total drop instead of only slope?

Because total drop is often the number people need in the field when checking elevations or setting a layout.

Can I use either inches per foot or percentage?

Yes. The calculator supports both a drop-per-foot input and a slope-percentage input so you can work in the basis that is easier for the project.

Related tools

Keep comparing

Use these related tools to compare nearby scenarios, check a second estimate, or keep narrowing down the right decision.

Home ToolsUpdated April 14, 2026