How to use it
- Enter length in feet
- Enter width in feet
- Enter thickness in inches
- Read cubic yards, bags, and cubic feet
Stop guessing how much concrete you need. This calculator converts your slab dimensions into cubic yards, total bags, and cubic feet in one click. Enter the length and width in feet, then the thickness in inches — the tool handles the rest.
Why it matters: Ordering too little means costly delays. Ordering too much wastes money. The bag count uses the standard 80-lb bag yield of 0.6 cubic feet per bag, so you know exactly how many to buy.
Read the results: Cubic yards help you place bulk orders with a ready-mix truck. Bags tell you the exact count for small jobs. Cubic feet gives you a cross-check. Round up slightly to cover waste, but avoid over-ordering by more than 5%.
Use this for driveways, patios, footings, or any flat concrete pour where you know the three dimensions. For a 10 ft × 10 ft slab at 4 inches thick, you get roughly 1.2 cubic yards, about 56 bags, or 33.3 cubic feet.
Pro tips
- Add 5–10% waste allowance for spillage and uneven subgrades
- Round bag counts up to whole bags — partial bags aren't sold
- Order ready-mix by cubic yard with a 0.5-yard buffer minimum
- Common mistake: forgetting to convert inches to feet before calculating
Real-life examples
- Pouring a backyard patio slab
- Estimating concrete for a driveway repair
- Calculating footings for a deck build
Case study
Sarah poured a 10×10 patio at 4" thick. The calculator showed 1.2 cubic yards and 56 bags. She ordered 1.5 yards of ready-mix and 56 bags — perfect fit, zero waste.