UniHive › Free tools › Concrete Calculator
Concrete Calculator
Enter the slab size and thickness. We add 10% for waste so you don't come up short. Free, no sign-up, and nothing leaves your device.
Questions
How thick should a slab be?
About 4 inches for sidewalks and patios, and 5 to 6 inches where vehicles drive. Check local building rules for anything structural.
How much does a bag make?
A typical 80 lb bag of concrete mix makes about 0.6 cubic feet, and a 60 lb bag about 0.45 cubic feet.