Guide · Updated November 2026 · How we check our numbers

How Much Concrete Do I Need? Cubic Yards and Bags

Ordering too little concrete is a big problem halfway through a pour, so it pays to calculate carefully and add a margin.

Step 1: volume in cubic feet

Multiply length × width (in feet) × thickness (in inches ÷ 12). A 10 × 10 ft patio, 4 inches thick, is 10 × 10 × 0.333 = 33.33 ft³.

Step 2: cubic yards

Ready-mix is sold by the cubic yard, which is 27 ft³. 33.33 ÷ 27 = 1.23 cubic yards.

Step 3: add extra

Uneven ground, forms that bow and spills use more than the math says. Add about 10%: 36.67 ft³ or 1.36 cubic yards.

Bags or truck?

Typical premix yields are about 0.60 ft³ per 80 lb bag, 0.45 ft³ per 60 lb bag and 0.30 ft³ per 40 lb bag. Our patio would need about 62 bags of 80 lb — over two tons to mix by hand. For more than about a cubic yard, a ready-mix truck is usually easier.

Thickness guide

Walkways and patios are commonly 4 inches thick; driveways are often 4–6 inches. Check local building codes and soil conditions.

Try the calculators

This guide is general information, not professional advice.