Concrete for a 32×32 slab
12.64 cubic yards (626 × 80 lb bags)
for a 32×32 ft slab 4 inches thick: 341.3 cu ft. Bag counts include 10% extra; at 6 inches you need 18.96 yards.
A 32×32 foot slab covers 1024 square feet. At the standard 4 inch thickness for a patio, walkway or shed floor, that is 341.3 cubic feet of concrete, or 12.64 cubic yards. At this size ready-mix is cheaper and far less work than bags: about 14 yards, roughly $2,310 before delivery fees, against $4,069 for 626 bags of 80 lb mix.
Concrete for a 32×32 slab by thickness
| Thickness | Cubic yards | Cubic feet | 80 lb bags | 60 lb bags | 40 lb bags |
|---|---|---|---|---|---|
| 3 in | 9.48 | 256 | 470 | 626 | 939 |
| 4 in | 12.64 | 341.3 | 626 | 835 | 1252 |
| 5 in | 15.8 | 426.7 | 783 | 1043 | 1565 |
| 6 in | 18.96 | 512 | 939 | 1252 | 1878 |
| 8 in | 25.28 | 682.7 | 1252 | 1669 | 2504 |
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: 32 × 32 × 0.333 = 341.33 cu ft.
- Divide by 27 for cubic yards: 341.33 ÷ 27 = 12.642 cu yd.
- Add 10% and divide by the bag yield: 375.47 ÷ 0.6 = 626 bags of 80 lb mix (rounded up).
Under the slab, plan on 4 inches of compacted gravel: about 12.64 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
- 30×32 slab
- 28×32 slab
- 32×36 slab
- 26×32 slab
- 25×32 slab
- 24×32 slab
- 32×40 slab
- 22×32 slab
- 20×32 slab
- 18×32 slab
- 16×32 slab
- 15×32 slab
Questions
- How many bags of concrete do I need for a 32×32 slab?
- At 4 inches thick, a 32×32 slab takes 626 bags of 80 lb concrete mix, 835 bags of 60 lb mix or 1252 bags of 40 lb mix, including 10% extra.
- How many yards of concrete for a 32×32 slab?
- 12.64 cubic yards at 4 inches thick, 15.8 at 5 inches and 18.96 at 6 inches, before adding extra for waste.
- How much does a 32×32 concrete slab cost?
- The concrete alone for a 4 inch 32×32 slab costs about $4,069 in 626 bags of 80 lb mix (at about $7 a bag) or about $2,310 for 14 yards of ready-mix (at about $165 a yard, before delivery fees). Professionally poured slabs usually run $6 to $12 per square foot, about $6,144 to $12,288 for 1024 sq ft.
- How much does a 32×32 slab weigh?
- About 24.7 tons at 4 inches thick (concrete weighs about 145 lb per cubic foot).