Concrete Yard Calculator
Calculate the cubic yards of concrete you need to order. Enter your pour dimensions and get your cubic yard total instantly — exactly the number readymix suppliers need from you.
Want to see the material cost too? Try the Concrete Estimator →
This concrete yard calculator is for one purpose: answering the question of how many cubic yards of concrete do I need. Readymix suppliers quote and deliver by the cubic yard, not by cubic feet or bags, so that is the output that matters. Enter your pour's length and width in feet and your depth in inches, and this tool will convert concrete to cubic yards instantly — displaying the result first and largest. Cubic feet and bag counts are included as secondary outputs for reference. For anything over 1 cubic yard, call a readymix supplier — this tool gives you the number to have ready when you do.
How to Use the Concrete Yard Calculator
- Enter your pour's length and width in feet.
- Enter depth in inches — not feet.
- Click "Calculate Cubic Yards" to see your cubic yard total.
- Add at least 10% overage before calling your supplier: multiply your yard total by 1.1.
- Ask your supplier about minimum order quantities and short-load fees before committing.
Cubic Yard Reference: Common Pour Sizes
Here are cubic yard totals for common pour dimensions at 4-inch and 6-inch thickness:
| Dimensions | 4 inches thick | 6 inches thick |
|---|---|---|
| 10 × 10 ft | 1.23 cu yd | 1.85 cu yd |
| 12 × 16 ft | 2.37 cu yd | 3.56 cu yd |
| 20 × 20 ft | 4.94 cu yd | 7.41 cu yd |
| 20 × 40 ft | 9.88 cu yd | 14.81 cu yd |
| 24 × 24 ft | 7.11 cu yd | 10.67 cu yd |
Add 10% to any of these numbers before ordering. A 20×20 pour at 4 inches should be ordered as 5.44 cubic yards to account for waste and spillage.
When to Use This Calculator
Before calling a readymix concrete supplier. Whether you need the yards of concrete for a driveway, a garage floor, or a patio, suppliers ask for cubic yards. Walking in with the number ready — not "about 10×20 at 4 inches" — gets you an accurate quote faster and prevents over- or under-ordering on a delivery you can't easily adjust.
Verifying a contractor's material quote. If a contractor tells you they need 8 yards for a 20×30 driveway at 4 inches, you can verify that in seconds: 20 × 30 × (4/12) ÷ 27 = 7.41 yards, plus 10% = 8.15 yards. That math checks out. If they're quoting 12 yards for the same job, you have a question to ask.
Deciding on pour thickness before ordering. Running your dimensions at two different depths takes seconds and shows you exactly how much more concrete a thicker slab requires. Going from 4 to 6 inches on a 20×20 pad adds 2.47 cubic yards — about $370 at $150/yard. That is the data you need to make an informed trade-off.
Frequently Asked Questions
How do I calculate cubic yards of concrete?
The formula is: cubic yards = (length × width × (depth ÷ 12)) ÷ 27. For a 20×20 slab at 4 inches: (20 × 20 × 0.333) ÷ 27 = 133.33 ÷ 27 = 4.94 cubic yards. This calculator does that conversion automatically and keeps cubic yards as the primary output since it is the number you actually need when placing a concrete order.
How many cubic yards of concrete do I need for a driveway?
A 20×40 driveway at 4 inches thick requires 9.88 cubic yards. At 6 inches the same driveway needs 14.81 cubic yards. A single-car driveway at 10×20 and 4 inches needs 2.47 cubic yards. Add 10% overage before ordering — a 20×40 at 4 inches becomes a 10.87-yard order. Call your supplier the day before to confirm the readymix truck can access your site.
How many cubic yards is a bag of concrete?
A 60lb bag covers 0.45 cubic feet, which is 0.017 cubic yards. An 80lb bag covers 0.60 cubic feet, or 0.022 cubic yards. As a cubic yard concrete bag calculator, this tool works in both directions — to convert from yards to bags: 1 cubic yard = 60 60lb bags, or 45 80lb bags. At those quantities, mixing bags by hand for anything over half a cubic yard becomes a serious labor question worth comparing against a readymix delivery cost.
How many cubic yards of concrete do I need for a 10x10 slab?
A 10×10 slab at 4 inches thick is 1.23 cubic yards. Most readymix suppliers have a 1-yard minimum, so this falls just above it — though you may pay a short-load fee since most trucks carry 5–8 yards. At 3.5 inches it is 1.08 yards. If you are close to the minimum threshold, consider whether adding depth or area to reach a more efficient order quantity makes sense for your project.
How much does a cubic yard of concrete weigh?
Wet concrete weighs approximately 4,000 pounds per cubic yard — about 2 tons. Cured concrete is slightly lighter at around 3,600 pounds per cubic yard. This is why readymix concrete is delivered by specialized trucks rather than pickup beds, and why even a 1-yard order requires a dedicated vehicle. A 20×20 pour at 4 inches is 4.94 yards — nearly 10 tons of wet concrete being placed in a single session.