How much concrete for a 8×20 slab 4 inches thick?
Answer
1.98 cubic yards
75 bags of 80lb concrete mix119 bags of 60lb mix~$297 for ready-mix
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How We Calculated This
Cubic yards = (L × W × D/12) / 27
(20 × 8 × 4/12) / 27 = 53.33 / 27 = 1.98 cubic yards
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Calculated using verified formulas. Last updated March 2026.