How much concrete for a 15×15 slab 5 inches thick?
Answer
3.47 cubic yards
131 bags of 80lb concrete mix209 bags of 60lb mixOrder ready-mix delivery (~$521)Add 10% for waste = 3.82 cy
Need a custom calculation?
Open the full calculator with custom inputs
How We Calculated This
Cubic yards = (L × W × D/12) / 27
(15 × 15 × 5/12) / 27 = 93.75 / 27 = 3.47 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.