Concrete for a 3×14 slab
0.52 cubic yards (26 × 80 lb bags)
for a 3×14 ft slab 4 inches thick: 14 cu ft. Bag counts include 10% extra; at 6 inches you need 0.78 yards.
A 3×14 foot slab covers 42 square feet. At the standard 4 inch thickness for a patio, walkway or shed floor, that is 14 cubic feet of concrete, or 0.52 cubic yards. That is a small enough pour for bagged mix: 26 bags of 80 lb at about $169.
Concrete for a 3×14 slab by thickness
| Thickness | Cubic yards | Cubic feet | 80 lb bags | 60 lb bags | 40 lb bags |
|---|---|---|---|---|---|
| 3 in | 0.39 | 10.5 | 20 | 26 | 39 |
| 4 in | 0.52 | 14 | 26 | 35 | 52 |
| 5 in | 0.65 | 17.5 | 33 | 43 | 65 |
| 6 in | 0.78 | 21 | 39 | 52 | 77 |
| 8 in | 1.04 | 28 | 52 | 69 | 103 |
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: 14 × 3 × 0.333 = 14 cu ft.
- Divide by 27 for cubic yards: 14 ÷ 27 = 0.519 cu yd.
- Add 10% and divide by the bag yield: 15.4 ÷ 0.6 = 26 bags of 80 lb mix (rounded up).
Under the slab, plan on 4 inches of compacted gravel: about 0.52 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
- 3×15 slab
- 3×12 slab
- 3×16 slab
- 3×10 slab
- 3×18 slab
- 4×14 slab
- 3×8 slab
- 3×20 slab
- 3×6 slab
- 3×22 slab
- 3×5 slab
- 5×14 slab
Questions
- How many bags of concrete do I need for a 3×14 slab?
- At 4 inches thick, a 3×14 slab takes 26 bags of 80 lb concrete mix, 35 bags of 60 lb mix or 52 bags of 40 lb mix, including 10% extra.
- How many yards of concrete for a 3×14 slab?
- 0.52 cubic yards at 4 inches thick, 0.65 at 5 inches and 0.78 at 6 inches, before adding extra for waste.
- How much does a 3×14 concrete slab cost?
- The concrete alone for a 4 inch 3×14 slab costs about $169 in 26 bags of 80 lb mix (at about $7 a bag) or about $124 for 0.75 yards of ready-mix (at about $165 a yard, before delivery fees). Professionally poured slabs usually run $6 to $12 per square foot, about $252 to $504 for 42 sq ft.
- How much does a 3×14 slab weigh?
- About 1 tons at 4 inches thick (concrete weighs about 145 lb per cubic foot).