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Concrete Yard Calculator — Convert to Cubic Yards

Enter your slab dimensions or a known volume to instantly convert to cubic yards, cubic feet, and cubic meters. See how many bags you need. Free, no signup required.

Concrete Yard Calculator

Convert dimensions or volume to cubic yards

Enter your dimensions or volume above to see results

How to Calculate Cubic Yards of Concrete

Concrete is ordered and priced by the cubic yard in the United States. Before you call a ready-mix plant or purchase bagged concrete, you need to know how many cubic yards your project requires. The calculation is straightforward: multiply length by width by thickness (all in feet), then divide by 27. The result is your volume in cubic yards.

For example, a 12-foot by 20-foot driveway at 4 inches thick works out to 12 × 20 × 0.333 = 80 cubic feet, divided by 27 = 2.96 cubic yards. With a 10 percent waste factor, you would order 3.26 cubic yards, which most suppliers would round up to 3.5 cubic yards for a standard short-load order.

What Is a Cubic Yard?

A cubic yard is a cube measuring 3 feet on each side, giving a volume of 27 cubic feet. It is the standard unit used by the US concrete industry. A single cubic yard of concrete weighs roughly 4,050 pounds (about 2 tons) and covers different areas depending on the thickness:

  • At 3 inches thick: covers approximately 108 square feet
  • At 4 inches thick: covers approximately 81 square feet
  • At 6 inches thick: covers approximately 54 square feet
  • At 8 inches thick: covers approximately 40 square feet

Converting Cubic Feet to Cubic Yards

The conversion factor is simple: there are exactly 27 cubic feet in one cubic yard. To convert cubic feet to cubic yards, divide by 27. To convert cubic yards to cubic feet, multiply by 27. This relationship comes from the fact that 1 yard = 3 feet, and a cube with 3-foot sides has a volume of 3 × 3 × 3 = 27 cubic feet.

Common conversions: 27 cubic feet = 1 cubic yard. 13.5 cubic feet = 0.5 cubic yards. 54 cubic feet = 2 cubic yards. 135 cubic feet = 5 cubic yards. If you know your volume in cubic feet, simply use the Direct Volume tab in the calculator above and select ft³ to get the cubic yard equivalent instantly.

Converting Cubic Meters to Cubic Yards

One cubic meter equals approximately 1.30795 cubic yards. One cubic yard equals approximately 0.7646 cubic meters. If you are working from metric plans or importing materials, you will encounter cubic meters. Enter your volume in the Direct Volume tab and select m³ to see the equivalent in cubic yards.

International projects and some engineering specifications use cubic meters. In Canada, concrete is also commonly sold by the cubic meter. Always confirm with your supplier which unit they quote in before placing an order.

Common Project Volume Examples

Here are typical concrete volumes for common residential projects to help you calibrate your estimates:

  • 10 x 10 ft patio at 4 in: 1.23 cubic yards (order 1.4 with waste)
  • 12 x 20 ft driveway at 4 in: 2.96 cubic yards (order 3.3 with waste)
  • 20 x 30 ft garage floor at 4 in: 7.41 cubic yards (order 8.2 with waste)
  • Footing 24 in x 12 in x 20 ft: 0.74 cubic yards per linear run
  • 12-inch round column, 8 ft tall: 0.31 cubic yards each

Why Add a 10% Waste Factor?

Concrete calculations assume perfectly flat, perfectly smooth subgrades and zero spillage. In practice, subgrades are rarely perfectly level, forms are not always perfect, and some concrete remains in the chute at the end of the pour. A 10 percent waste allowance covers these real-world losses and ensures you do not run short mid-pour.

Running short of concrete mid-pour is a serious problem. A cold joint forms where the fresh concrete meets the partially set concrete, creating a structural weakness. It is almost always better to order slightly more than you need. Any leftover concrete can be used for small footings, steps, or other minor fill work around the project site.

Ordering Ready-Mix vs. Buying Bags

For projects under 0.5 cubic yards (about 13.5 cubic feet), bagged concrete is often more practical. Ready-mix plants typically have minimum order quantities of 1 cubic yard and charge short-load fees for orders under 5 cubic yards. For small projects, the delivery fee and minimum order charge make bagged concrete more economical even though the per-yard material cost is higher.

For projects above 1 cubic yard, ready-mix becomes more competitive. The bags needed section in the calculator above shows how many 40 lb, 60 lb, and 80 lb bags your project requires, which makes it easy to compare the bagged route versus calling a ready-mix plant. Use the +10% waste column numbers when purchasing bags to account for mixing losses.

Frequently Asked Questions

What is a cubic yard of concrete?
A cubic yard is a volume equal to 3 feet by 3 feet by 3 feet, or 27 cubic feet. It is the standard unit used by ready-mix concrete suppliers in the United States. When you order concrete by the truckload, the price is quoted per cubic yard. One cubic yard weighs approximately 4,050 pounds (about 2 tons) and is enough to pour a 10-foot by 10-foot slab at 3.3 inches thick.
How do I convert cubic feet to cubic yards?
Divide the number of cubic feet by 27 to get cubic yards. For example, 81 cubic feet divided by 27 equals 3 cubic yards. The formula is: cubic yards = cubic feet / 27. This works because one cubic yard contains exactly 27 cubic feet (3 ft x 3 ft x 3 ft = 27 ft³). The calculator above performs this conversion automatically when you enter dimensions or a direct volume.
How do I convert cubic meters to cubic yards?
To convert cubic meters to cubic yards, multiply the cubic meters by 1.30795. For example, 2 cubic meters times 1.30795 equals approximately 2.616 cubic yards. Alternatively, 1 cubic yard equals 0.764555 cubic meters. The calculator handles this conversion in both directions: enter a volume in cubic meters using the Direct Volume tab and it will instantly show the equivalent in cubic yards and cubic feet.
How many cubic yards do I need for a 10x10 slab at 4 inches thick?
A 10 by 10 foot slab at 4 inches thick requires 1.23 cubic yards of concrete. Here is how to calculate it: convert 4 inches to feet (4 / 12 = 0.333 ft), then multiply length x width x thickness: 10 x 10 x 0.333 = 33.3 cubic feet, and divide by 27 to get 1.23 cubic yards. Always order at least 10 percent more to account for spillage and subgrade variations, so order 1.35 cubic yards for this project.
Why do contractors order concrete in cubic yards?
Cubic yards is the industry standard unit for ordering ready-mix concrete in the United States. Ready-mix trucks are sized in cubic yards, pricing is quoted per cubic yard, and batch plant software is built around this unit. Contractors convert their project dimensions to cubic yards before calling the plant. For international projects or when working with metric plans, cubic meters may be used instead, but most domestic US suppliers will still quote in yards.
How much waste factor should I add when ordering concrete?
A standard recommendation is to add 10 percent to your calculated volume when ordering concrete. This accounts for spillage during the pour, slightly uneven subgrade that consumes more concrete than the nominal calculation, and concrete that remains in the truck chute. For slabs with complex shapes, footings with non-uniform depth, or rough subgrades, some contractors add 15 percent. It is always better to have a small amount left over than to run short mid-pour.

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