Whether you're pouring a patio, setting fence posts, or building a foundation, knowing how much concrete you need is critical. Too little means a trip back to the store; too much is wasted money.
How Concrete Volume Is Calculated
Volume = Length × Width × Height
Concrete is typically measured in cubic yards or cubic meters. For a simple slab:
Example: 10ft × 10ft × 4in Slab
1. Convert all measurements to feet: 4in = 0.333ft
2. Volume = 10 × 10 × 0.333 = 33.3 cubic feet
3. Convert to cubic yards: 33.3 ÷ 27 = 1.23 cubic yards
Concrete Bag Calculator
| Bag Size | Cubic Feet | Bags per Cubic Yard |
|---|---|---|
| 40 lb | 0.30 cu ft | 90 bags |
| 60 lb | 0.45 cu ft | 60 bags |
| 80 lb | 0.60 cu ft | 45 bags |
For our example (1.23 cubic yards):
- 40 lb bags: 1.23 × 90 = 111 bags
- 60 lb bags: 1.23 × 60 = 74 bags
- 80 lb bags: 1.23 × 45 = 56 bags
Cost Estimation
- Ready-mix concrete: $100-$150 per cubic yard
- Bagged concrete (80 lb): $5-$7 per bag
- Delivery fee: $50-$200 (varies by location)
For our 1.23 cubic yard slab:
- Ready-mix: ~$150-$200 (plus delivery)
- Bagged (80 lb): 56 bags × $6 = ~$336
Types of Concrete Projects
| Project | Typical Thickness |
|---|---|
| Patio/Sidewalk | 4 inches |
| Driveway | 6 inches |
| Garage floor | 4-6 inches |
| Footings | 8-12 inches |
| Fence posts | 8-12 inches diameter |
Try Our Concrete Calculator
Our Concrete Calculator helps you:
- Calculate volume in cubic yards and cubic meters
- Get bag count for 40, 60, and 80 lb bags
- Estimate total cost based on your local prices
- Save money by ordering the exact amount needed
💡 Pro Tip: Always order 10% more concrete than your calculation. It's better to have a little extra than to run short — especially with ready-mix deliveries!
*Calculate your concrete needs with our free Concrete Calculator.*
