How much concrete for a 18×25 slab 6 inches thick?
Answer
8.33 cubic yards
313 bags of 80lb concrete mix500 bags of 60lb mixOrder ready-mix delivery (~$1,250)Add 10% for waste = 9.16 cy
Need a custom calculation?
Open the full calculator with custom inputs
How We Calculated This
Cubic yards = (L × W × D/12) / 27
(25 × 18 × 6/12) / 27 = 225.00 / 27 = 8.33 cubic yards
Related Calculations
How much concrete for a 4×4 slab 4 inches thick?0.20 cubic yardsHow much concrete for a 4×4 slab 5 inches thick?0.25 cubic yardsHow much concrete for a 4×4 slab 6 inches thick?0.30 cubic yardsHow much concrete for a 4×4 slab 8 inches thick?0.40 cubic yardsHow much concrete for a 4×6 slab 4 inches thick?0.30 cubic yards
Calculated using verified formulas. Last updated March 2026.