Concrete for a 12×24 Slab at 4" Thick
A 12 ft × 24 ft slab poured 4 inches thick is 288 sq ft and needs 3.56 cubic yards of concrete — order 3.84 CY to cover 8% waste, or about 173 80-lb bags for a small pour. Adjust the dimensions below for your project.
Concrete needed
3.56 cu yd
Slab area
288 sq ft
Concrete needed
3.56 cubic yards3.84 CY with 8% waste — order this much
80-lb bags
173 bagsor 231 × 60-lb bags
Ready-mix cost (est.)
$672~$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.