Enter your project dimensions to estimate the cubic yards of ready-mix concrete needed. Typical for slabs, patios, footings, and driveway pours.
Enter your project dimensions and click Calculate to see your estimate.
Typical materials for a concrete pour
Ready-mix volume is an estimate. Add waste for spillage and uneven subgrade, then verify with your supplier.
Concrete volume is calculated from slab length, width, and thickness. Ready-mix is ordered in cubic yards, with waste added for spillage and uneven subgrade.
Results are planning estimates based on typical assumptions. Verify quantities with product labels and your project layout before purchase. How we calculate
A 20×20 slab at 4 inches thick needs about 4.9 cubic yards of concrete before waste. At 6 inches thick, you need about 7.4 cubic yards. Enter your dimensions in the calculator for a planning estimate.
Residential patios and walkways are typically 4 inches thick. Driveways and heavy-load areas often use 5–6 inches. Always check local building codes for your project.
There are 27 cubic feet in one cubic yard. Our calculator converts automatically so you can order ready-mix by the cubic yard.
Yes. Add 5–10% for spillage, uneven subgrade, and form variations. Running short on a pour is costly. The calculator includes a waste allowance.
Bagged concrete suits small projects under about 1 cubic yard — post holes, small pads, and repairs. Larger slabs are usually cheaper with ready-mix delivery.
Measure form height at several points across the pour area. Slabs should be uniform depth; low spots may need additional fill before placing concrete.
No. This calculator estimates concrete volume only. A compacted gravel base is recommended under most slabs but is ordered separately.
