Concrete for a 10×20 Slab at 4" Thick
A 10 ft × 20 ft slab poured 4 inches thick is 200 sq ft and needs 2.47 cubic yards of concrete — order 2.67 CY to cover 8% waste, or about 120 80-lb bags for a small pour. Adjust the dimensions below for your project.
Concrete needed
2.47 cu yd
Slab area
200 sq ft
Concrete needed
2.47 cubic yards2.67 CY with 8% waste — order this much
80-lb bags
120 bagsor 160 × 60-lb bags
Ready-mix cost (est.)
$467~$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.