Concrete footing calculator
Select continuous footings, square pads or a slab with a thickened edge. Next, provide the length, width and depth in inches.
Cubic yards per foot of footing
| Footing (width x depth) | Cubic feet per foot | Yards per 10 ft | Yards per 100 ft | 100 ft with 10% extra |
|---|---|---|---|---|
| 12 x 6 in | 0.50 | 0.19 | 1.85 | 2.04 |
| 16 x 8 in | 0.89 | 0.33 | 3.29 | 3.62 |
| 20 x 10 in | 1.39 | 0.51 | 5.14 | 5.66 |
| 24 x 12 in | 2.00 | 0.74 | 7.41 | 8.15 |
The International Residential Code (IRC R403.1.1 and R403.1.4) requires footings at least 12 in wide, at least 6 in thick, and set at least 12 in beneath the undisturbed ground. Your building department gives you the local figure, and soil and frost depth can mean you need more.
Monolithic slab calculator
A single pour forms a monolithic slab and its footing together. That footing is a deeper band that runs around the edge. The tool adds the slab first, then adds the band by multiplying the band's full width by the depth under the slab. For a slab measuring 24 by 24 ft, with a thickness of 4 in and a 12 by 12 in edge, adding 10% brings the total to 10.32 cubic yards. On its own, the slab takes 7.82 cubic yards, with the same 10% extra.