Our concrete calculator helps you work out how many cubic metres or cubic feet of concrete you need for a project. It supports three common shapes: rectangular slabs (for driveways, patios, and floors), cylindrical columns (for fence posts and pillars), and rectangular footings (for foundations). Enter the dimensions and the calculator gives you the volume in both metric and imperial units, along with an estimate of how many pre-mixed bags you would need. Always add 5–10% extra to account for waste and spillage.