Concrete for a 14×15 slab
2.59 cubic yards (129 × 80 lb bags)
for a 14×15 ft slab 4 inches thick: 70 cu ft. Bag counts include 10% extra; at 6 inches you need 3.89 yards.
A 14×15 foot slab covers 210 square feet. At the standard 4 inch thickness for a patio, walkway or shed floor, that is 70 cubic feet of concrete, or 2.59 cubic yards. At this size you can mix 129 bags of 80 lb (about $839 and a long day of mixing) or order 3 yards of ready-mix (about $495, plus the short-load fee most suppliers charge under 3 to 4 yards).
Concrete for a 14×15 slab by thickness
| Thickness | Cubic yards | Cubic feet | 80 lb bags | 60 lb bags | 40 lb bags |
|---|---|---|---|---|---|
| 3 in | 1.94 | 52.5 | 97 | 129 | 193 |
| 4 in | 2.59 | 70 | 129 | 172 | 257 |
| 5 in | 3.24 | 87.5 | 161 | 214 | 321 |
| 6 in | 3.89 | 105 | 193 | 257 | 385 |
| 8 in | 5.19 | 140 | 257 | 343 | 514 |
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: 15 × 14 × 0.333 = 70 cu ft.
- Divide by 27 for cubic yards: 70 ÷ 27 = 2.593 cu yd.
- Add 10% and divide by the bag yield: 77 ÷ 0.6 = 129 bags of 80 lb mix (rounded up).
Under the slab, plan on 4 inches of compacted gravel: about 2.59 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
- 14×14 slab
- 14×16 slab
- 15×15 slab
- 12×15 slab
- 15×16 slab
- 12×14 slab
- 14×18 slab
- 10×15 slab
- 15×18 slab
- 10×14 slab
- 14×20 slab
- 8×15 slab
Questions
- How many bags of concrete do I need for a 14×15 slab?
- At 4 inches thick, a 14×15 slab takes 129 bags of 80 lb concrete mix, 172 bags of 60 lb mix or 257 bags of 40 lb mix, including 10% extra.
- How many yards of concrete for a 14×15 slab?
- 2.59 cubic yards at 4 inches thick, 3.24 at 5 inches and 3.89 at 6 inches, before adding extra for waste.
- How much does a 14×15 concrete slab cost?
- The concrete alone for a 4 inch 14×15 slab costs about $839 in 129 bags of 80 lb mix (at about $7 a bag) or about $495 for 3 yards of ready-mix (at about $165 a yard, before delivery fees). Professionally poured slabs usually run $6 to $12 per square foot, about $1,260 to $2,520 for 210 sq ft.
- How much does a 14×15 slab weigh?
- About 5.1 tons at 4 inches thick (concrete weighs about 145 lb per cubic foot).