Concrete Coverage: Square Feet and Cubic Feet per Yard

Coverage by thickness

A cubic yard is 27 cubic feet. To find how many square feet it covers, divide 27 by the thickness in feet. Here is that math done for the common depths.

Most patios and walkways are poured at 4 inches, driveways at 4 to 6 inches, and footings deeper still. The thicker the pour, the less ground a single yard covers.

How the units relate

People mix up cubic feet, cubic yards, and square feet, so here is the plain version.

• Cubic feet and cubic yards both measure volume, which is the actual amount of concrete. 27 cubic feet equals 1 cubic yard. Concrete is ordered in cubic yards.
• Square feet measures area, which is the flat surface you are covering. Square feet alone does not tell you how much concrete you need. You have to pair it with a thickness to get a volume.

That is the key idea: area plus thickness gives volume. A 100 square foot patio needs very different amounts of concrete at 4 inches versus 6 inches, even though the surface area is identical.

Working backward from your area

If you know the square footage you want to cover and the thickness, you can find the yards you need. Multiply the area by the thickness in feet, then divide by 27.

For a 300 square foot driveway at 4 inches:

• 300 x 0.33 = 99 cubic feet
• 99 ÷ 27 = 3.67 cubic yards

The concrete calculator runs this for you and adds a waste cushion, so you can go straight from your measurements to an order number without touching the arithmetic.