How Many Bags of Concrete for an 8x8 Slab?
Small pads like an 8x8 suit bagged mix. How many bags of concrete for an 8x8 slab at a standard 4-inch depth: 36 × 80 lb, or 48 × 60 lb, since each bag yields only about 0.6 or 0.45 cubic feet.
Concrete calculator →How the bag count is figured
- Area: 8 × 8 = 64 sq ft.
- Volume at 4 in: 64 × 0.333 = 21.33 cu ft.
- 80 lb bags: 21.33 ÷ 0.60 = 35.6, round up to 36.
- 60 lb bags: 21.33 ÷ 0.45 = 47.4, round up to 48.
Check the yield printed on your brand’s bag, since it varies a little. The concrete calculator handles other shapes.
Related: How Much Concrete for an 8x60 Slab?
Bags by thickness for an 8x8 slab
| Thickness | Cubic feet | 80 lb bags | 60 lb bags | 40 lb bags |
|---|---|---|---|---|
| 3 in | 16.00 | 27 | 36 | 54 |
| 4 in | 21.33 | 36 | 48 | 72 |
| 5 in | 26.67 | 45 | 60 | 89 |
| 6 in | 32.00 | 54 | 72 | 107 |
Bags or a truck?
At 0.79 cubic yards, this pad is near the point where a ready-mix truck starts to make sense. Many plants charge a small-load fee on tiny orders, so bags are often cheaper here, and a rented mixer makes 36 bags manageable for two people.
Related: How Many Bags of Concrete for a 10x10 Slab?
Forms and base
Dig out sod and soft soil, compact the bottom and add a few inches of compacted gravel. Set 2x4 forms level or with a slight slope for drainage, stake them every couple of feet and check the diagonals so the pad is square. Keep the fresh slab damp or covered for several days so it cures instead of drying out.
Buying the bags
A pallet of 80 lb bags often holds around 40 to 42 bags, so this job is about 1 pallet or less. Buy one or two extra bags: returning an unopened bag is easier than running out mid-pour.
Questions people ask
How many 80 lb bags for an 8x8 slab?
About 36 bags at 4 inches thick.
How many 60 lb bags for an 8x8 slab?
About 48 bags at 4 inches thick.
How many bags for an 8x8 slab 6 inches thick?
About 54 bags of 80 lb mix or 72 of 60 lb.
How much does an 80 lb bag of concrete yield?
About 0.6 cubic feet of mixed concrete.
When is bagged concrete practical?
Usually for jobs under about a cubic yard. Beyond that, mixing dozens of bags by hand gets slow and batches may not blend well.
Related guides
- How Much Area Does a Yard of Concrete Cover?
- How Many Bags of Concrete in a Yard? 40, 60, 80 lb
- Gravel Base Under a Concrete Slab: Depth and Tons
- How Many Yards in a Concrete Truck? Mixer Sizes
- Concrete Short Load Fee: What It Is and How to Cut It
- 60 lb vs 80 lb Concrete Bags: Yield, Count, and Cost
- Rebar vs Wire Mesh in a Slab: Which One to Use
- How Many Bags of Concrete for a 6x10 Slab?
- How Many Bags of Concrete for a 7x7 Slab?
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