Concrete for a 12×22 slab
3.26 cubic yards (162 × 80 lb bags)
for a 12×22 ft slab 4 inches thick: 88 cu ft. Bag counts include 10% extra; at 6 inches you need 4.89 yards.
A 12×22 foot slab covers 264 square feet. At the standard 4 inch thickness for a patio, walkway or shed floor, that is 88 cubic feet of concrete, or 3.26 cubic yards. At this size ready-mix is cheaper and far less work than bags: about 3.75 yards, roughly $619 before delivery fees, against $1,053 for 162 bags of 80 lb mix.
Concrete for a 12×22 slab by thickness
| Thickness | Cubic yards | Cubic feet | 80 lb bags | 60 lb bags | 40 lb bags |
|---|---|---|---|---|---|
| 3 in | 2.44 | 66 | 121 | 162 | 242 |
| 4 in | 3.26 | 88 | 162 | 216 | 323 |
| 5 in | 4.07 | 110 | 202 | 269 | 404 |
| 6 in | 4.89 | 132 | 242 | 323 | 484 |
| 8 in | 6.52 | 176 | 323 | 431 | 646 |
Bag counts include 10% extra for spillage and uneven ground. Cubic yards and cubic feet are the exact volume.
How it’s worked out
- Convert the thickness to feet: 4 in ÷ 12 = 0.333 ft.
- Multiply length × width × thickness: 22 × 12 × 0.333 = 88 cu ft.
- Divide by 27 for cubic yards: 88 ÷ 27 = 3.259 cu yd.
- Add 10% and divide by the bag yield: 96.8 ÷ 0.6 = 162 bags of 80 lb mix (rounded up).
Under the slab, plan on 4 inches of compacted gravel: about 3.26 cubic yards. For driveways and anything that carries a vehicle, go to 5 or 6 inches and add rebar or wire mesh.
Change the numbers
Other slab sizes
- 12×20 slab
- 12×24 slab
- 12×25 slab
- 10×22 slab
- 14×22 slab
- 12×18 slab
- 12×26 slab
- 15×22 slab
- 12×16 slab
- 12×28 slab
- 12×15 slab
- 8×22 slab
Questions
- How many bags of concrete do I need for a 12×22 slab?
- At 4 inches thick, a 12×22 slab takes 162 bags of 80 lb concrete mix, 216 bags of 60 lb mix or 323 bags of 40 lb mix, including 10% extra.
- How many yards of concrete for a 12×22 slab?
- 3.26 cubic yards at 4 inches thick, 4.07 at 5 inches and 4.89 at 6 inches, before adding extra for waste.
- How much does a 12×22 concrete slab cost?
- The concrete alone for a 4 inch 12×22 slab costs about $1,053 in 162 bags of 80 lb mix (at about $7 a bag) or about $619 for 3.75 yards of ready-mix (at about $165 a yard, before delivery fees). Professionally poured slabs usually run $6 to $12 per square foot, about $1,584 to $3,168 for 264 sq ft.
- How much does a 12×22 slab weigh?
- About 6.4 tons at 4 inches thick (concrete weighs about 145 lb per cubic foot).