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Deck Footing Calculator

Estimate concrete volume needed for round deck footings.

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

Why this page exists

Deck planning gets easier when footing dimensions are turned into a concrete estimate instead of being guessed from the number of holes alone. This calculator helps visitors estimate concrete volume per footing and total concrete volume for round deck footings using simple cylinder math.

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

Deck footing calculator

Estimate concrete volume for round deck footings from footing diameter, depth, and footing count.

Result

1.57 cubic yards

Estimated concrete volume for round deck footings based on cylinder-volume math and the footing count entered.

Total concrete volume1.57 cu yd

Volume per footing5.30 cu ft

Total concrete in cubic feet42.41 cu ft

Number of footings used8

Each 18 inch by 36 inch round footing holds about 5.30 cubic feet of concrete.
8 footings brings the total to about 42.41 cubic feet, or 1.57 cubic yards.
Use the result as a planning number only, because footing shape, flare, and code requirements can change the final amount of concrete needed.

This is a planning estimate. Real footing size, hole shape, rebar, bell bottoms, and code requirements can all change the amount of concrete needed.

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

Enter footing diameter, footing depth, and the number of footings.

The calculator finds the volume of one round footing using cylinder volume math.

It multiplies that volume by the footing count and shows the total concrete needed.

Understanding your result

This is a practical concrete estimate only. Real footing holes may flare, bell out, or follow local code requirements that change the final volume.

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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.

Estimate concrete before ordering bags or delivery

A cubic-yard total can make it easier to decide whether the project fits bagged concrete or a bulk order better.

Compare deeper or wider footing options

Changing diameter or depth can show how quickly footing size changes the total concrete volume.

Use it with other deck-planning tools

Deck footing estimates often fit naturally beside concrete, joist, and fastener tools.

FAQ

Common questions

How is footing volume calculated here?

The calculator uses cylinder volume math for each round footing and then multiplies that amount by the number of footings entered.

Why show volume per footing and total volume?

Per-footing volume helps you understand the size of each hole, while the total helps with ordering concrete for the full project.

Why can the final concrete amount differ from the estimate?

Because real holes may not be perfectly cylindrical, and local code or design choices can change footing size and shape.

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 11, 2026