Concrete for a 15×26 slab
4.81 cubic yards (239 × 80 lb bags)
for a 15×26 ft slab 4 inches thick: 130 cu ft. Bag counts include 10% extra; at 6 inches you need 7.22 yards.
A 15×26 foot slab covers 390 square feet. At the standard 4 inch thickness for a patio, walkway or shed floor, that is 130 cubic feet of concrete, or 4.81 cubic yards. At this size ready-mix is cheaper and far less work than bags: about 5.5 yards, roughly $908 before delivery fees, against $1,554 for 239 bags of 80 lb mix.
Concrete for a 15×26 slab by thickness
| Thickness | Cubic yards | Cubic feet | 80 lb bags | 60 lb bags | 40 lb bags |
|---|---|---|---|---|---|
| 3 in | 3.61 | 97.5 | 179 | 239 | 358 |
| 4 in | 4.81 | 130 | 239 | 318 | 477 |
| 5 in | 6.02 | 162.5 | 298 | 398 | 596 |
| 6 in | 7.22 | 195 | 358 | 477 | 715 |
| 8 in | 9.63 | 260 | 477 | 636 | 954 |
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: 26 × 15 × 0.333 = 130 cu ft.
- Divide by 27 for cubic yards: 130 ÷ 27 = 4.815 cu yd.
- Add 10% and divide by the bag yield: 143 ÷ 0.6 = 239 bags of 80 lb mix (rounded up).
Under the slab, plan on 4 inches of compacted gravel: about 4.81 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
- 15×25 slab
- 14×26 slab
- 16×26 slab
- 15×24 slab
- 15×28 slab
- 15×22 slab
- 15×30 slab
- 12×26 slab
- 18×26 slab
- 15×20 slab
- 15×32 slab
- 15×18 slab
Questions
- How many bags of concrete do I need for a 15×26 slab?
- At 4 inches thick, a 15×26 slab takes 239 bags of 80 lb concrete mix, 318 bags of 60 lb mix or 477 bags of 40 lb mix, including 10% extra.
- How many yards of concrete for a 15×26 slab?
- 4.81 cubic yards at 4 inches thick, 6.02 at 5 inches and 7.22 at 6 inches, before adding extra for waste.
- How much does a 15×26 concrete slab cost?
- The concrete alone for a 4 inch 15×26 slab costs about $1,554 in 239 bags of 80 lb mix (at about $7 a bag) or about $908 for 5.5 yards of ready-mix (at about $165 a yard, before delivery fees). Professionally poured slabs usually run $6 to $12 per square foot, about $2,340 to $4,680 for 390 sq ft.
- How much does a 15×26 slab weigh?
- About 9.4 tons at 4 inches thick (concrete weighs about 145 lb per cubic foot).