Concrete for a 4×16 slab
0.79 cubic yards (40 × 80 lb bags)
for a 4×16 ft slab 4 inches thick: 21.3 cu ft. Bag counts include 10% extra; at 6 inches you need 1.19 yards.
A 4×16 foot slab covers 64 square feet. At the standard 4 inch thickness for a patio, walkway or shed floor, that is 21.3 cubic feet of concrete, or 0.79 cubic yards. That is a small enough pour for bagged mix: 40 bags of 80 lb at about $260.
Concrete for a 4×16 slab by thickness
| Thickness | Cubic yards | Cubic feet | 80 lb bags | 60 lb bags | 40 lb bags |
|---|---|---|---|---|---|
| 3 in | 0.59 | 16 | 30 | 40 | 59 |
| 4 in | 0.79 | 21.3 | 40 | 53 | 79 |
| 5 in | 0.99 | 26.7 | 49 | 66 | 98 |
| 6 in | 1.19 | 32 | 59 | 79 | 118 |
| 8 in | 1.58 | 42.7 | 79 | 105 | 157 |
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: 16 × 4 × 0.333 = 21.33 cu ft.
- Divide by 27 for cubic yards: 21.33 ÷ 27 = 0.79 cu yd.
- Add 10% and divide by the bag yield: 23.47 ÷ 0.6 = 40 bags of 80 lb mix (rounded up).
Under the slab, plan on 4 inches of compacted gravel: about 0.79 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
- 4×15 slab
- 4×14 slab
- 4×18 slab
- 3×16 slab
- 4×12 slab
- 4×20 slab
- 5×16 slab
- 4×10 slab
- 4×22 slab
- 4×8 slab
- 4×24 slab
- 6×16 slab
Questions
- How many bags of concrete do I need for a 4×16 slab?
- At 4 inches thick, a 4×16 slab takes 40 bags of 80 lb concrete mix, 53 bags of 60 lb mix or 79 bags of 40 lb mix, including 10% extra.
- How many yards of concrete for a 4×16 slab?
- 0.79 cubic yards at 4 inches thick, 0.99 at 5 inches and 1.19 at 6 inches, before adding extra for waste.
- How much does a 4×16 concrete slab cost?
- The concrete alone for a 4 inch 4×16 slab costs about $260 in 40 bags of 80 lb mix (at about $7 a bag) or about $165 for 1 yards of ready-mix (at about $165 a yard, before delivery fees). Professionally poured slabs usually run $6 to $12 per square foot, about $384 to $768 for 64 sq ft.
- How much does a 4×16 slab weigh?
- About 1.5 tons at 4 inches thick (concrete weighs about 145 lb per cubic foot).