How much concrete for a 24×40 slab 8 inches thick?
Answer
23.70 cubic yards
889 bags of 80lb concrete mix1423 bags of 60lb mixOrder ready-mix delivery (~$3,555)Add 10% for waste = 26.07 cy
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How We Calculated This
Cubic yards = (L × W × D/12) / 27
(40 × 24 × 8/12) / 27 = 640.00 / 27 = 23.70 cubic yards
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Calculated using verified formulas. Last updated March 2026.