Concrete for a 5×25 slab
1.54 cubic yards (77 × 80 lb bags)
for a 5×25 ft slab 4 inches thick: 41.7 cu ft. Bag counts include 10% extra; at 6 inches you need 2.31 yards.
A 5×25 foot slab covers 125 square feet. At the standard 4 inch thickness for a patio, walkway or shed floor, that is 41.7 cubic feet of concrete, or 1.54 cubic yards. At this size you can mix 77 bags of 80 lb (about $501 and a long day of mixing) or order 1.75 yards of ready-mix (about $289, plus the short-load fee most suppliers charge under 3 to 4 yards).
Concrete for a 5×25 slab by thickness
| Thickness | Cubic yards | Cubic feet | 80 lb bags | 60 lb bags | 40 lb bags |
|---|---|---|---|---|---|
| 3 in | 1.16 | 31.3 | 58 | 77 | 115 |
| 4 in | 1.54 | 41.7 | 77 | 102 | 153 |
| 5 in | 1.93 | 52.1 | 96 | 128 | 191 |
| 6 in | 2.31 | 62.5 | 115 | 153 | 230 |
| 8 in | 3.09 | 83.3 | 153 | 204 | 306 |
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: 25 × 5 × 0.333 = 41.67 cu ft.
- Divide by 27 for cubic yards: 41.67 ÷ 27 = 1.543 cu yd.
- Add 10% and divide by the bag yield: 45.83 ÷ 0.6 = 77 bags of 80 lb mix (rounded up).
Under the slab, plan on 4 inches of compacted gravel: about 1.54 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
- 5×24 slab
- 5×26 slab
- 5×22 slab
- 5×28 slab
- 4×25 slab
- 5×20 slab
- 5×30 slab
- 6×25 slab
- 5×18 slab
- 5×32 slab
- 5×16 slab
- 3×25 slab
Questions
- How many bags of concrete do I need for a 5×25 slab?
- At 4 inches thick, a 5×25 slab takes 77 bags of 80 lb concrete mix, 102 bags of 60 lb mix or 153 bags of 40 lb mix, including 10% extra.
- How many yards of concrete for a 5×25 slab?
- 1.54 cubic yards at 4 inches thick, 1.93 at 5 inches and 2.31 at 6 inches, before adding extra for waste.
- How much does a 5×25 concrete slab cost?
- The concrete alone for a 4 inch 5×25 slab costs about $501 in 77 bags of 80 lb mix (at about $7 a bag) or about $289 for 1.75 yards of ready-mix (at about $165 a yard, before delivery fees). Professionally poured slabs usually run $6 to $12 per square foot, about $750 to $1,500 for 125 sq ft.
- How much does a 5×25 slab weigh?
- About 3 tons at 4 inches thick (concrete weighs about 145 lb per cubic foot).