4 Inch Concrete Slab Estimate

Estimate concrete for a 4 inch slab from length, width, cubic feet, cubic yards, and waste.

Use the 4 inch factor

Four inches equals one third of a foot. Multiply square footage by 0.333 to get cubic feet.

Divide cubic feet by 27 to get cubic yards for ready-mix.

A 5-10% allowance is common for small slab planning. Uneven ground may need more.

Forms, stakes, gravel base, reinforcement, and finishing tools are not included in concrete volume.

Is 4 inches enough for every slab?

No. Slab thickness depends on use, load, soil, and local requirements.

Can I use 0.33 instead of 0.333?

Yes for a rough estimate, but exact calculations use 4 divided by 12.

Does compaction change concrete volume?

Compaction affects the base, not the concrete volume inside the forms.

Open the calculators and enter your dimensions to estimate materials before you shop.