Concrete Slab Calculator Guide

Learn how concrete slab volume is converted from feet and inches into cubic yards.

Measure length and width

Record the slab footprint in feet. Use the largest rectangle that covers the pour, then split irregular shapes into smaller rectangles.

Slab thickness is usually measured in inches. Convert it to feet by dividing by 12 before calculating cubic feet.

Concrete is commonly ordered by cubic yard. Divide cubic feet by 27 to get cubic yards.

Add waste for grade variation, edge forms, and spillage. Many small slabs use 5-10% extra.

Why order extra concrete?

Subgrade variation and small measurement errors can use more concrete than the exact math suggests.

Can I use bags instead of ready-mix?

Small pads can use bags. Larger pours are usually easier with ready-mix delivery.

Does the calculator include reinforcement?

No. Rebar, mesh, and forms depend on the project requirements.

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