How Much Concrete for a 12x12 Slab
Estimate ready-mix concrete or bag count for a 12x12 slab using thickness and waste.
Calculate area
A 12x12 slab is 144 square feet. Thickness determines the final concrete volume.
Use common thickness
At 4 inches thick, the slab volume is 144 x 0.333 cubic feet before conversion.
Convert and round
Divide cubic feet by 27 for cubic yards, then round up after adding waste.
Check forms and base
A level compacted base helps the slab use the expected amount of concrete.
FAQ
How many cubic yards for a 12x12 four-inch slab?
The exact math is about 1.78 cubic yards before waste.
Does a thicker edge change the estimate?
Yes. Thickened edges and footings should be added separately.
Should I include gravel base?
No. Gravel base is a separate material estimate.
Related guides
Next step
Open the calculators and enter your dimensions to estimate materials before you shop.