Concrete for a 36×50 slab
22.22 cubic yards (1100 × 80 lb bags)
for a 36×50 ft slab 4 inches thick: 600 cu ft. Bag counts include 10% extra; at 6 inches you need 33.33 yards.
A 36×50 foot slab covers 1800 square feet. At the standard 4 inch thickness for a patio, walkway or shed floor, that is 600 cubic feet of concrete, or 22.22 cubic yards. At this size ready-mix is cheaper and far less work than bags: about 24.5 yards, roughly $4,043 before delivery fees, against $7,150 for 1100 bags of 80 lb mix.
Concrete for a 36×50 slab by thickness
| Thickness | Cubic yards | Cubic feet | 80 lb bags | 60 lb bags | 40 lb bags |
|---|---|---|---|---|---|
| 3 in | 16.67 | 450 | 825 | 1100 | 1650 |
| 4 in | 22.22 | 600 | 1100 | 1467 | 2200 |
| 5 in | 27.78 | 750 | 1375 | 1834 | 2750 |
| 6 in | 33.33 | 900 | 1650 | 2200 | 3300 |
| 8 in | 44.44 | 1,200 | 2200 | 2934 | 4400 |
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: 50 × 36 × 0.333 = 600 cu ft.
- Divide by 27 for cubic yards: 600 ÷ 27 = 22.222 cu yd.
- Add 10% and divide by the bag yield: 660 ÷ 0.6 = 1100 bags of 80 lb mix (rounded up).
Under the slab, plan on 4 inches of compacted gravel: about 22.22 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
- 32×50 slab
- 40×50 slab
- 30×50 slab
- 36×40 slab
- 28×50 slab
- 26×50 slab
- 36×36 slab
- 25×50 slab
- 24×50 slab
- 32×36 slab
- 22×50 slab
- 50×50 slab
Questions
- How many bags of concrete do I need for a 36×50 slab?
- At 4 inches thick, a 36×50 slab takes 1100 bags of 80 lb concrete mix, 1467 bags of 60 lb mix or 2200 bags of 40 lb mix, including 10% extra.
- How many yards of concrete for a 36×50 slab?
- 22.22 cubic yards at 4 inches thick, 27.78 at 5 inches and 33.33 at 6 inches, before adding extra for waste.
- How much does a 36×50 concrete slab cost?
- The concrete alone for a 4 inch 36×50 slab costs about $7,150 in 1100 bags of 80 lb mix (at about $7 a bag) or about $4,043 for 24.5 yards of ready-mix (at about $165 a yard, before delivery fees). Professionally poured slabs usually run $6 to $12 per square foot, about $10,800 to $21,600 for 1800 sq ft.
- How much does a 36×50 slab weigh?
- About 43.5 tons at 4 inches thick (concrete weighs about 145 lb per cubic foot).