Concrete Volume & Cost Calculator
Estimate how many cubic yards of concrete you need for a slab, pad, or footing — plus total material cost with waste and delivery. Ideal for DIYers and contractors planning pours.
About this calculator
Concrete is ordered in cubic yards. First, convert your slab dimensions from feet and inches into cubic feet: multiply length × width × (thickness ÷ 12). Divide by 27 to convert cubic feet to cubic yards. A waste factor (typically 5–10%) is added to account for spills, uneven subgrades, and over-pour at edges. The full formula is: Cost = ((length × width × (thickness / 12)) / 27) × (1 + wastePercent / 100) × pricePerYard. For example, a 20 ft × 20 ft slab at 4 inches thick yields about 4.94 cubic yards before waste. Multiplying by 1.10 for 10% waste and by the price per yard gives the total material cost.
How to use
Suppose you're pouring a 20 ft × 15 ft driveway at 4 inches thick, with a 10% waste factor and concrete priced at $150/yd³. Step 1 — cubic yards before waste: (20 × 15 × (4 / 12)) / 27 = (100) / 27 ≈ 3.70 yd³. Step 2 — apply waste: 3.70 × (1 + 10/100) = 3.70 × 1.10 = 4.07 yd³. Step 3 — total cost: 4.07 × $150 = $610.50. You'd order approximately 4.1 cubic yards and budget around $611 for material alone.
Frequently asked questions
How much waste factor should I add when ordering concrete?
Most contractors recommend a 5–10% waste factor for standard slabs and footings. Add 10% for irregular shapes or sloped ground where over-pour is more likely. For large commercial pours with tight forms, 5% is often sufficient. It is always better to order slightly more than needed, since a short pour that requires a second truck trip is far more expensive than leftover concrete.
How do I convert concrete from cubic feet to cubic yards?
One cubic yard equals 27 cubic feet, so divide your cubic-foot volume by 27. For example, a slab that is 200 cubic feet in volume equals 200 ÷ 27 ≈ 7.41 cubic yards. Ready-mix suppliers always quote prices per cubic yard, so making this conversion before calling is essential. This calculator does the division automatically once you enter length, width, and thickness.
What is the average price of concrete per cubic yard in the US?
Ready-mix concrete typically costs between $120 and $180 per cubic yard in the United States, though prices vary significantly by region, mix strength (PSI), and fuel costs. Short-load fees may apply if you order less than a full truck (usually 8–10 yd³). Delivery charges, pump truck rental, and finishing labor are additional costs not included in the per-yard price. Always get at least two local quotes before finalizing your budget.