Free Concrete Calculator

Measure the length, width, and thickness of your project area. Multiply all three dimensions together to get volume in cubic feet, then divide by 27 to convert to cubic yards. Our calculator handles this automatically for you.

A 10x10 foot slab at 4 inches thick requires approximately 1.23 cubic yards of concrete. That equals roughly 56 bags of 80-lb concrete mix, 72 bags of 60-lb mix, or 112 bags of 40-lb mix.

The standard thickness for a residential concrete slab is 4 inches. Driveways and garage floors typically require 5-6 inches. For heavy loads or commercial use, 6-8 inches may be needed.

Ready-mix concrete typically costs between $120 and $200 per cubic yard, depending on your location, mix type, and delivery distance. The national average is around $150 per cubic yard in 2026.

Yes, always order 5-10% more concrete than your calculated amount to account for spillage, uneven subgrade, and form variations. Running short mid-pour creates weak cold joints.

3000 PSI concrete is the standard mix for sidewalks, patios, and slabs. 4000 PSI is a higher-strength mix used for driveways, garage floors, and structural elements that bear heavier loads.

One cubic yard of concrete requires approximately 45 bags of 80-lb concrete mix. Each 80-lb bag yields approximately 0.6 cubic feet, or about 0.022 cubic yards of mixed concrete.

Bags are practical for small projects under 1 cubic yard (fence posts, small pads). For anything over 1-2 cubic yards, ready-mix truck delivery is more cost-effective and produces better results.

Yes. Use the rectangular slab shape for spread footings, the tube/column shape for pier footings, or calculate multiple sections separately and add the volumes together.

The calculator gives you the exact volume based on your dimensions. We recommend adding 5-10% to the result for waste, spillage, and subgrade irregularities when placing your order.