Concrete for a 22×40 slab
10.86 cubic yards (538 × 80 lb bags)
for a 22×40 ft slab 4 inches thick: 293.3 cu ft. Bag counts include 10% extra; at 6 inches you need 16.3 yards.
A 22×40 foot slab covers 880 square feet. At the standard 4 inch thickness for a patio, walkway or shed floor, that is 293.3 cubic feet of concrete, or 10.86 cubic yards. At this size ready-mix is cheaper and far less work than bags: about 12 yards, roughly $1,980 before delivery fees, against $3,497 for 538 bags of 80 lb mix.
Concrete for a 22×40 slab by thickness
| Thickness | Cubic yards | Cubic feet | 80 lb bags | 60 lb bags | 40 lb bags |
|---|---|---|---|---|---|
| 3 in | 8.15 | 220 | 404 | 538 | 807 |
| 4 in | 10.86 | 293.3 | 538 | 718 | 1076 |
| 5 in | 13.58 | 366.7 | 673 | 897 | 1345 |
| 6 in | 16.3 | 440 | 807 | 1076 | 1614 |
| 8 in | 21.73 | 586.7 | 1076 | 1435 | 2152 |
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: 40 × 22 × 0.333 = 293.33 cu ft.
- Divide by 27 for cubic yards: 293.33 ÷ 27 = 10.864 cu yd.
- Add 10% and divide by the bag yield: 322.67 ÷ 0.6 = 538 bags of 80 lb mix (rounded up).
Under the slab, plan on 4 inches of compacted gravel: about 10.86 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
- 20×40 slab
- 24×40 slab
- 22×36 slab
- 25×40 slab
- 18×40 slab
- 26×40 slab
- 22×32 slab
- 22×30 slab
- 22×50 slab
- 16×40 slab
- 28×40 slab
- 22×28 slab
Questions
- How many bags of concrete do I need for a 22×40 slab?
- At 4 inches thick, a 22×40 slab takes 538 bags of 80 lb concrete mix, 718 bags of 60 lb mix or 1076 bags of 40 lb mix, including 10% extra.
- How many yards of concrete for a 22×40 slab?
- 10.86 cubic yards at 4 inches thick, 13.58 at 5 inches and 16.3 at 6 inches, before adding extra for waste.
- How much does a 22×40 concrete slab cost?
- The concrete alone for a 4 inch 22×40 slab costs about $3,497 in 538 bags of 80 lb mix (at about $7 a bag) or about $1,980 for 12 yards of ready-mix (at about $165 a yard, before delivery fees). Professionally poured slabs usually run $6 to $12 per square foot, about $5,280 to $10,560 for 880 sq ft.
- How much does a 22×40 slab weigh?
- About 21.3 tons at 4 inches thick (concrete weighs about 145 lb per cubic foot).