Cubic yards by slab size
| Slab size | 4 in thick | 5 in thick | 6 in thick |
|---|---|---|---|
| 4 × 4 ft | 0.20 yd³ | 0.25 yd³ | 0.30 yd³ |
| 5 × 5 ft | 0.31 yd³ | 0.39 yd³ | 0.46 yd³ |
| 6 × 6 ft | 0.44 yd³ | 0.56 yd³ | 0.67 yd³ |
| 8 × 8 ft | 0.79 yd³ | 0.99 yd³ | 1.19 yd³ |
| 10 × 10 ft | 1.23 yd³ | 1.54 yd³ | 1.85 yd³ |
| 10 × 12 ft | 1.48 yd³ | 1.85 yd³ | 2.22 yd³ |
| 12 × 12 ft | 1.78 yd³ | 2.22 yd³ | 2.67 yd³ |
| 12 × 16 ft | 2.37 yd³ | 2.96 yd³ | 3.56 yd³ |
| 16 × 16 ft | 3.16 yd³ | 3.95 yd³ | 4.74 yd³ |
| 20 × 20 ft | 4.94 yd³ | 6.17 yd³ | 7.41 yd³ |
| 20 × 24 ft | 5.93 yd³ | 7.41 yd³ | 8.89 yd³ |
| 24 × 24 ft | 7.11 yd³ | 8.89 yd³ | 10.67 yd³ |
These are geometric volumes only. Many projects should include an additional material allowance before ordering.
Concrete cubic yard formula
Multiply length × width × thickness to find cubic feet, making sure thickness is converted from inches to feet. Then divide cubic feet by 27 because one cubic yard contains 27 cubic feet.
Example: 10 × 10 slab at 4 inches
A 10 × 10 ft slab at 4 inches thick contains about 1.23 cubic yards of net concrete. With a 10% extra-material allowance, the planning quantity becomes about 1.36 cubic yards. The BuildGauge Concrete Calculator also rounds that to a practical ready-mix ordering quantity.
Calculate your exact concrete quantity
Enter any length, width, thickness and waste allowance to compare cubic yards, cubic feet, ready-mix order quantity and bag counts.
Open Concrete Calculator →Common slab thicknesses
Thickness should come from the project design and intended use, not from a generic chart. A thicker slab increases concrete volume directly, so even a 1-inch change can materially affect the order on a larger project.
For bag counts, patios, driveways, footings and post holes, browse the Concrete Planning Hub.