How Much Concrete for a 5x5 Pad?
Concrete needed
0.34 cubic yards
A 5 by 5 foot pad at four inches, with ten percent on top for waste.
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How that number is worked out
These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.
- Length5 ft
- Width5 ft
- Thickness4 in
- Waste allowance10 %
Concrete needed0.34 cubic yards
| Volume | 8.3 cu ft |
|---|---|
| Cubic yards before waste | 0.31 |
| Cubic yards with 10% waste | 0.34order to this number |
| Order in quarter yards | 0.5 cu yd |
| 60 lb bags, if bagging it | 21 |
| 80 lb bags, if bagging it | 16 |
The material list this produces
| Ready mix concrete, cubic yards | 0.5 |
|---|---|
| Rebar or mesh, sq ft of slab | 25 |
| Form lumber, linear ft | 20 |
Thickness compared
Thickness is the one number on this page worth arguing about, so here is the same slab at each of the usual four.
| Thickness | Concrete needed |
|---|---|
| 4 in | 0.34 cubic yards |
| 5 in | 0.42 cubic yards |
| 6 in | 0.51 cubic yards |
| 8 in | 0.68 cubic yards |
What else matters here
Twenty one bags, about a third of a yard, and no control joints. That last part is the useful bit: the rule of thumb for a four inch slab is a joint every eight to ten feet, so a pad five feet square does not need one at all.
Slabs crack because concrete shrinks as it cures and something has to give. A control joint is a deliberate weak line that decides where the crack goes. Below about six feet there is not enough shrinkage across the pad to force one, so cutting a joint into a 5 by 5 just gives it a reason to break in half.
What does matter at this size is finishing. A small pad is finished quickly and it is tempting to overwork the surface while the bleed water is still up, which traps water under the surface and leaves it dusty and weak. Wait for the sheen to go before floating it.
What this calculator assumes
- One cubic yard is 27 cubic feet. A 4 inch slab is one third of a foot thick, not 4.
- A 60 lb bag yields about 0.45 cubic feet and an 80 lb bag about 0.60. Bags are for small pours only; past about one cubic yard, ready mix is cheaper and far less work.
- Ready mix is usually sold in quarter yard steps with a short load fee below one yard.
Questions people ask
How many bags of concrete for a 5x5 pad?
About 21 sixty pound bags or 16 eighty pound bags at 4 inches thick, waste included.
Does a 5x5 slab need control joints?
No. Joints go in roughly every eight to ten feet on a four inch slab, so a pad this size does not need one and is better without.
Why does a small slab end up dusty on top?
Almost always from finishing too early. Working the surface while bleed water is still on it traps that water in the top layer and leaves it weak.
The concrete calculator takes any dimensions you like and hands back the same list.