How much concrete for a 18×24 slab 8 inches thick?
Answer
10.67 cubic yards
401 bags of 80lb concrete mix640 bags of 60lb mixOrder ready-mix delivery (~$1,601)Add 10% for waste = 11.74 cy
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How We Calculated This
Cubic yards = (L × W × D/12) / 27
(24 × 18 × 8/12) / 27 = 288.00 / 27 = 10.67 cubic yards
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Calculated using verified formulas. Last updated March 2026.