How much concrete for a 40×50 slab 8 inches thick?
Answer
49.38 cubic yards
1852 bags of 80lb concrete mix2963 bags of 60lb mixOrder ready-mix delivery (~$7,407)Add 10% for waste = 54.32 cy
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How We Calculated This
Cubic yards = (L × W × D/12) / 27
(50 × 40 × 8/12) / 27 = 1333.33 / 27 = 49.38 cubic yards
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Calculated using verified formulas. Last updated March 2026.