How Many Bags of Concrete for a 5x5 Slab?
How many bags of concrete for a 5x5 slab: about 14 bags of 80 lb mix at 4 inches thick, or 19 bags of 60 lb mix. The slab is 25 square feet, which at 4 inches is 8.33 cubic feet of concrete.
Concrete calculator →How the bag count is figured
- Area: 5 × 5 = 25 sq ft.
- Volume at 4 in: 25 × 0.333 = 8.33 cu ft.
- 80 lb bags: 8.33 ÷ 0.60 = 13.9, round up to 14.
- 60 lb bags: 8.33 ÷ 0.45 = 18.5, round up to 19.
Check the yield printed on your brand’s bag, since it varies a little. The concrete calculator handles other shapes.
Related: How Much Sand for a 5x5 Sandbox?
Bags by thickness for a 5x5 slab
| Thickness | Cubic feet | 80 lb bags | 60 lb bags | 40 lb bags |
|---|---|---|---|---|
| 3 in | 6.25 | 11 | 14 | 21 |
| 4 in | 8.33 | 14 | 19 | 28 |
| 5 in | 10.42 | 18 | 24 | 35 |
| 6 in | 12.50 | 21 | 28 | 42 |
Bags or a truck?
Bags win on small pads because there is no delivery or short-load charge. The tradeoff is labor: 14 bags of 80 lb mix is 1,120 pounds to lift, pour and mix. A small drum mixer keeps batches consistent, and a helper keeps the pour moving so the edges do not set before the middle.
Related: How Many Bags of Concrete for a 10x10 Slab?
Forms and base
A small slab still needs a firm base. Compact the soil, add compacted gravel and set forms to the finished height. If the pad will hold an AC unit, a generator or a grill, keep the top a little above the surrounding grade so water does not pool against it. Mixing 14 bags takes time, so stage them next to the forms before you start.
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 a 5x5 slab?
About 14 bags at 4 inches thick.
How many 60 lb bags for a 5x5 slab?
About 19 bags at 4 inches thick.
How many bags for a 5x5 slab 6 inches thick?
About 21 bags of 80 lb mix or 28 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 5x8 Slab?
- How Many Bags of Concrete for a 4x8 Slab?
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