The Concrete Calculator

Multiply length × width × thickness (all in feet) to get cubic feet, then divide by 27 for cubic yards. The calculator above does this instantly, just enter your slab or footing dimensions.

Concrete is measured by volume: length × width × depth. Convert inches to feet (÷12), multiply the three dimensions, then divide by 27 to get cubic yards. Enter your numbers above for an exact figure.

A cubic yard of ready-mix concrete typically costs about $125–$165 delivered in the US, depending on PSI, region and load size. Short loads may add a fee.

A standard mixer truck holds about 10 cubic yards when full, though many deliver 8–11 yards. Partial loads are common but can carry a short-load charge.

It takes about 45 × 80 lb bags, 60 × 60 lb bags, or 90 × 40 lb bags to make one cubic yard of concrete. The bag calculator gives the exact count for your project.

One cubic yard of concrete weighs roughly 3,600–4,050 lb (about 1.8–2 tons). Standard concrete weighs about 150 lb per cubic foot.

A basic 4-inch poured slab typically runs $4–$8 per square foot, and more with reinforcement, decorative finishing or a thicker pour.

Divide the total volume in cubic feet by the bag yield: an 80 lb bag ≈ 0.60 cu ft, a 60 lb bag ≈ 0.45 cu ft, a 40 lb bag ≈ 0.30 cu ft. The calculator above handles this automatically.

An 80 lb bag of ready-mix usually costs about $5–$8, and a pallet (42–56 bags) runs roughly $250–$400 depending on brand and retailer.

An 80 lb bag yields about 0.60 cu ft, a 60 lb bag about 0.45 cu ft, and a 40 lb bag about 0.30 cu ft of mixed concrete.

At 4 inches thick, one cubic yard covers about 81 sq ft; at 5 inches about 65 sq ft; and at 6 inches about 54 sq ft.

Most residential slabs and patios are poured 4 inches thick. Driveways and load-bearing areas are typically 5–6 inches, often with rebar or wire mesh.