Concrete Volume Calculator: From Bags to Truckloads
Calculate concrete volume in cubic yards, 80lb bags, or truckloads. Free calculator for slabs, footings, columns, and stairs. Instant results.
Stop Over-Ordering Concrete
📊 Based on standard concrete mix ratios and industry practices. See our methodology page for formulas.
Ordering too much concrete wastes $150-180 per cubic yard. Ordering too little means a cold joint (a visible seam where the first pour stopped and the second began)—a permanent structural weakness. Most contractors add 10% to the calculated volume for waste and spillage. Our calculator helps you find the exact volume so you can add exactly the right safety margin.Bags vs Truck: The Cost Breakpoint
An 80lb bag of concrete mix yields about 0.6 cubic feet and costs $4.50-6.00. That's $270-360 per cubic yard equivalent. Ready-mix from a truck costs $150-180 per cubic yard (plus a short-load fee of $50-100 for orders under 5 yards). Breakpoint: If you need more than 1 cubic yard (about 45 80lb bags), a truck is cheaper—even with the short-load fee. For anything under 1 yard (fence post footings, small pad), bags are cheaper and you avoid the minimum delivery charge.
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Frequently Asked Questions
- How many 80lb bags of concrete per cubic yard?
- 45 bags. One 80lb bag yields 0.6 cubic feet. 27 cubic feet per cubic yard ÷ 0.6 = 45 bags. For 60lb bags: 60 bags per cubic yard (0.45 cubic feet per bag).
- How many cubic yards of concrete do I need for a 20×20 slab?
- At 4" thick: 20 × 20 × (4/12) ÷ 27 = 4.94 cubic yards ≈ 5 yards. At 6" thick: 20 × 20 × (6/12) ÷ 27 = 7.41 cubic yards ≈ 7.5 yards. Add 10% for waste: order 5.5 yards or 8.25 yards respectively.
- What is a short load fee for concrete?
- Most ready-mix companies charge $50-100 extra for orders under 5 cubic yards. The concrete itself is the same price, but they charge for the truck time and partial load. Some companies have a 3-yard minimum.