Concrete for a 12×12 Slab at 4" Thick
A 12 ft × 12 ft slab poured 4 inches thick is 144 sq ft and needs 1.78 cubic yards of concrete — order 1.92 CY to cover 8% waste, or about 87 80-lb bags for a small pour. Adjust the dimensions below for your project.
Concrete needed
1.78 cu yd
Slab area
144 sq ft
Concrete needed
1.78 cubic yards1.92 CY with 8% waste — order this much
80-lb bags
87 bagsor 116 × 60-lb bags
Ready-mix cost (est.)
$336~$175/CY delivered
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How this is calculated
Concrete volume = area × thickness. We convert to cubic yards (the unit ready-mix is sold in), then add 8% for spillage and over-ordering — the same waste factor used in professional estimating.