How much concrete for a 8×18 slab 8 inches thick?
Answer
3.56 cubic yards
134 bags of 80lb concrete mix214 bags of 60lb mixOrder ready-mix delivery (~$534)Add 10% for waste = 3.92 cy
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How We Calculated This
Cubic yards = (L × W × D/12) / 27
(18 × 8 × 8/12) / 27 = 96.00 / 27 = 3.56 cubic yards
Related Calculations
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Calculated using verified formulas. Last updated March 2026.