Concrete Calculator
Calculate how much concrete you need in cubic yards and cubic meters, plus the number of 60 lb or 80 lb bags required for any project.
ft
ft
in
Cubic Yards
—
Cubic Meters —
80 lb Bags (with 10% extra) —
60 lb Bags (with 10% extra) —
How to Use This Calculator
- Enter the length and width of the area in feet.
- Enter the depth (thickness) in inches.
- Results show cubic yards, cubic meters, and bags of 60 lb and 80 lb mix needed (including 10% buffer).
Formula
Cubic yards = (L × W × D_ft) ÷ 27
where D_ft = depth inches ÷ 12. | Cubic meters = cubic yards × 0.7646
80 lb bags = cubic yards × 45 | 60 lb bags = cubic yards × 60
Example
Example: 10 ft × 12 ft × 4 in slab → 1.48 cubic yards → 67 bags of 80 lb mix (with 10% buffer).
Frequently Asked Questions
- Multiply length (ft) × width (ft) × depth (ft) and divide by 27 to get cubic yards. This calculator does that automatically.
- One cubic yard of concrete requires approximately 45 bags of 80 lb mix, or 60 bags of 60 lb mix.
- Yes — order 5–10% extra to account for spillage and irregular forms. The calculator shows a 10% buffer in the results.
- Driveways typically use 4 inches (0.33 ft) of depth. Heavily loaded areas may need 6 inches.
- This calculator is for rectangular slabs. For circles, use π × r² for the area and enter it as length × 1 with width = area.