Concrete Calculator
Accurately estimate the cubic yardage or number of bags required for your concrete project. This tool supports slabs, circular columns, and even multi-step stairs.
How do I calculate concrete for a slab?
Multiply length × width × depth (thickness) in feet, then divide by 27 to get cubic yards. For example, a 10'x10' patio at 4" deep is 10 × 10 × 0.333 = 33.3 cu ft. 33.3 / 27 = 1.23 cubic yards.
What is the standard thickness for a concrete driveway?
A standard residential driveway is typically 4 inches thick. For heavier vehicles or machinery, 5 to 6 inches is recommended.
How many bags of concrete are in a cubic yard?
It depends on the bag size. Approximately 45 bags of 80lb concrete mix or 60 bags of 60lb concrete mix are needed to equal one cubic yard.
Should I add extra for waste?
Yes! It is standard practice to add 10% to your calculation to account for spillage, over-excavation, and inconsistencies in the subgrade.