Calculate concrete volume for slabs, footings, and columns. Free online concrete calculator with formula, examples, and FAQ.
The concrete calculator helps you determine how much concrete you need for your project. Whether you're pouring a slab, footing, or column, simply enter the dimensions to get the volume in cubic feet, cubic yards, and the number of concrete bags needed.
Volume (cu ft) = Length × Width × (Depth / 12) | Volume (cu yd) = Volume (cu ft) / 27Depth is divided by 12 to convert inches to feet. One cubic yard equals 27 cubic feet. An 80 lb bag of premixed concrete yields approximately 0.022 cubic yards (0.6 cu ft), while a 60 lb bag yields approximately 0.017 cubic yards (0.45 cu ft).
| Input | Output |
|---|---|
| 10×10 ft slab, 6" deep | Volume: 1.85 cu yd (50 cu ft), 84 bags (80 lb) or 111 bags (60 lb) |
| 20×20 ft slab, 4" deep | Volume: 4.94 cu yd (133.33 cu ft), 223 bags (80 lb) or 297 bags (60 lb) |
| 5×5 ft footing, 12" deep | Volume: 0.93 cu yd (25 cu ft), 42 bags (80 lb) or 56 bags (60 lb) |