How to Use the Concrete Calculator
Choose whether you're pouring a slab or footing (entering length, width, and thickness) or a round column (entering diameter and height), and the calculator finds the total volume in cubic feet and cubic yards, along with an estimated number of standard 40, 60, or 80 lb premixed bags.
The calculator handles both the volume math and the bag-count conversion, so you don't need to do either calculation separately.
Entering accurate measurements
As covered in the volume-calculation guide, thickness is the input most worth double-checking for accuracy, since it directly multiplies into the total volume and a small error there compounds across a large slab area.
Deciding between bags and ready-mix based on the result
As covered in the bagged-vs-ready-mix guide, use the calculator's cubic-yard result as your guide for which purchasing approach makes more sense — and remember to add the standard 5-10% waste buffer covered in the extra-concrete guide before finalizing how much to actually order.