Concrete for a 32×36 slab
14.22 cubic yards (704 × 80 lb bags)
for a 32×36 ft slab 4 inches thick: 384 cu ft. Bag counts include 10% extra; at 6 inches you need 21.33 yards.
A 32×36 foot slab covers 1152 square feet. At the standard 4 inch thickness for a patio, walkway or shed floor, that is 384 cubic feet of concrete, or 14.22 cubic yards. At this size ready-mix is cheaper and far less work than bags: about 15.75 yards, roughly $2,599 before delivery fees, against $4,576 for 704 bags of 80 lb mix.
Concrete for a 32×36 slab by thickness
| Thickness | Cubic yards | Cubic feet | 80 lb bags | 60 lb bags | 40 lb bags |
|---|---|---|---|---|---|
| 3 in | 10.67 | 288 | 528 | 704 | 1056 |
| 4 in | 14.22 | 384 | 704 | 939 | 1408 |
| 5 in | 17.78 | 480 | 880 | 1174 | 1760 |
| 6 in | 21.33 | 576 | 1056 | 1408 | 2112 |
| 8 in | 28.44 | 768 | 1408 | 1878 | 2816 |
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: 36 × 32 × 0.333 = 384 cu ft.
- Divide by 27 for cubic yards: 384 ÷ 27 = 14.222 cu yd.
- Add 10% and divide by the bag yield: 422.4 ÷ 0.6 = 704 bags of 80 lb mix (rounded up).
Under the slab, plan on 4 inches of compacted gravel: about 14.22 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
- 30×36 slab
- 32×32 slab
- 32×40 slab
- 28×36 slab
- 36×36 slab
- 30×32 slab
- 26×36 slab
- 25×36 slab
- 28×32 slab
- 24×36 slab
- 36×40 slab
- 26×32 slab
Questions
- How many bags of concrete do I need for a 32×36 slab?
- At 4 inches thick, a 32×36 slab takes 704 bags of 80 lb concrete mix, 939 bags of 60 lb mix or 1408 bags of 40 lb mix, including 10% extra.
- How many yards of concrete for a 32×36 slab?
- 14.22 cubic yards at 4 inches thick, 17.78 at 5 inches and 21.33 at 6 inches, before adding extra for waste.
- How much does a 32×36 concrete slab cost?
- The concrete alone for a 4 inch 32×36 slab costs about $4,576 in 704 bags of 80 lb mix (at about $7 a bag) or about $2,599 for 15.75 yards of ready-mix (at about $165 a yard, before delivery fees). Professionally poured slabs usually run $6 to $12 per square foot, about $6,912 to $13,824 for 1152 sq ft.
- How much does a 32×36 slab weigh?
- About 27.8 tons at 4 inches thick (concrete weighs about 145 lb per cubic foot).