Concrete Calculator
Calculate concrete volume and bags needed for a slab or footing.
About this tool
Estimate how much concrete you need for a slab, footing or pad, in both cubic yards (how ready-mix is ordered) and cubic feet, plus an estimated number of 80 lb pre-mix bags if you're not ordering ready-mix.
Key Features
- Cubic yards and cubic feet
- 80 lb bag estimate
- Works for any slab, footing or pad dimensions
How to Use
- Enter the length and width in feet.
- Enter the depth (thickness) in inches.
- Click Calculate Concrete.
Benefits
- Order the right amount of ready-mix concrete
- Estimate bag count for a DIY pour
- Avoid over- or under-ordering
Frequently Asked Questions
Yes — most contractors add 5–10% extra to account for spillage, uneven subgrade and form leakage. This calculator gives the exact theoretical volume; round up when ordering.
An 80 lb bag yields about 0.6 cubic feet of mixed concrete — the estimate uses that figure, but always check the actual yield printed on your specific bag, which can vary slightly by brand.