12×16 Concrete Slab Calculator
Start with a typical 4-inch slab below, compare common thicknesses, then customize the measurements in the full visual calculator.
12×16 slab at 4 inches thick
A 12×16 slab at 4 inches thick contains about 2.37 cubic yards before extra material. With a 10% allowance, plan for about 2.61 yd³; rounded to a quarter-yard ordering increment, that is 2.75 yd³.
How thickness changes the order
| Thickness | Concrete + 10% | Ready-mix order | 80-lb bags |
|---|---|---|---|
| 4 in | 2.61 yd³ | 2.75 yd³ | 118 |
| 5 in | 3.26 yd³ | 3.50 yd³ | 147 |
| 6 in | 3.91 yd³ | 4.00 yd³ | 177 |
Thickness should be selected for the actual project and loading requirements; this comparison is for quantity planning, not structural design.
Use the quantity to plan how you will buy concrete
At 4 inches, this project is approximately 118 80-lb bags, 157 60-lb bags, or 235 40-lb bags. Large bag counts mean a substantial amount of mixing and handling, so compare bagged material with ready-mix delivery before purchasing.
The full BuildGauge Concrete Calculator also shows 40, 50, 60 and 80-lb bags, project weight, waste allowance and a visual slab diagram.