Concrete for a 12×26 slab
3.85 cubic yards (191 × 80 lb bags)
for a 12×26 ft slab 4 inches thick: 104 cu ft. Bag counts include 10% extra; at 6 inches you need 5.78 yards.
A 12×26 foot slab covers 312 square feet. At the standard 4 inch thickness for a patio, walkway or shed floor, that is 104 cubic feet of concrete, or 3.85 cubic yards. At this size ready-mix is cheaper and far less work than bags: about 4.25 yards, roughly $701 before delivery fees, against $1,242 for 191 bags of 80 lb mix.
Concrete for a 12×26 slab by thickness
| Thickness | Cubic yards | Cubic feet | 80 lb bags | 60 lb bags | 40 lb bags |
|---|---|---|---|---|---|
| 3 in | 2.89 | 78 | 143 | 191 | 286 |
| 4 in | 3.85 | 104 | 191 | 255 | 382 |
| 5 in | 4.81 | 130 | 239 | 318 | 477 |
| 6 in | 5.78 | 156 | 286 | 382 | 572 |
| 8 in | 7.7 | 208 | 382 | 509 | 763 |
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 × 12 × 0.333 = 104 cu ft.
- Divide by 27 for cubic yards: 104 ÷ 27 = 3.852 cu yd.
- Add 10% and divide by the bag yield: 114.4 ÷ 0.6 = 191 bags of 80 lb mix (rounded up).
Under the slab, plan on 4 inches of compacted gravel: about 3.85 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
- 12×25 slab
- 12×24 slab
- 12×28 slab
- 12×22 slab
- 12×30 slab
- 10×26 slab
- 14×26 slab
- 12×20 slab
- 12×32 slab
- 15×26 slab
- 12×18 slab
- 8×26 slab
Questions
- How many bags of concrete do I need for a 12×26 slab?
- At 4 inches thick, a 12×26 slab takes 191 bags of 80 lb concrete mix, 255 bags of 60 lb mix or 382 bags of 40 lb mix, including 10% extra.
- How many yards of concrete for a 12×26 slab?
- 3.85 cubic yards at 4 inches thick, 4.81 at 5 inches and 5.78 at 6 inches, before adding extra for waste.
- How much does a 12×26 concrete slab cost?
- The concrete alone for a 4 inch 12×26 slab costs about $1,242 in 191 bags of 80 lb mix (at about $7 a bag) or about $701 for 4.25 yards of ready-mix (at about $165 a yard, before delivery fees). Professionally poured slabs usually run $6 to $12 per square foot, about $1,872 to $3,744 for 312 sq ft.
- How much does a 12×26 slab weigh?
- About 7.5 tons at 4 inches thick (concrete weighs about 145 lb per cubic foot).