How Much Concrete for a 6x6 Pad?
Concrete needed
0.49 cubic yards
A 6 by 6 foot pad at four inches, with ten percent on top for waste.
When the figures look right, the concrete material list downloads as a real PDF with your business details on it, built inside your own browser. Nothing you type is uploaded anywhere.
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.
- Length6 ft
- Width6 ft
- Thickness4 in
- Waste allowance10 %
Concrete needed0.49 cubic yards
| Volume | 12 cu ft |
|---|---|
| Cubic yards before waste | 0.44 |
| Cubic yards with 10% waste | 0.49order to this number |
| Order in quarter yards | 0.5 cu yd |
| 60 lb bags, if bagging it | 30 |
| 80 lb bags, if bagging it | 22 |
The material list this produces
| Ready mix concrete, cubic yards | 0.5 |
|---|---|
| Rebar or mesh, sq ft of slab | 36 |
| Form lumber, linear ft | 24 |
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 | 0.49 cubic yards |
| 5 in | 0.61 cubic yards |
| 6 in | 0.73 cubic yards |
| 8 in | 0.98 cubic yards |
What else matters here
Half a cubic yard, and this is the practical ceiling for mixing by hand. Twenty two eighty pound bags is roughly 1,760 pounds of material to open, tip, mix and place, and all of it has to go in wet on wet before the first of it starts to set.
That timing is the whole difficulty. Concrete begins to stiffen in under an hour in warm weather, and a pad poured in two sessions with a gap between them has a cold joint through the middle: a plane with no bond across it, which is a crack that was built in rather than one that developed.
With a mixer and two people, thirty bags is comfortable. With a wheelbarrow and a shovel it is not, and this is the size where people discover that. If it has to be hand mixed, have everything cut, formed, wetted and laid out before the first bag is opened.
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 6x6 pad?
About 30 sixty pound bags or 22 eighty pound bags at 4 inches thick, waste included.
Is a 6x6 slab too big to mix by hand?
It is right at the limit. With a mixer and two people it is straightforward. With a wheelbarrow and a hoe it is a long job and it risks a cold joint through the middle.
What is a cold joint?
The plane where fresh concrete meets concrete that has already started to set. There is no bond across it, so it behaves like a crack that was built into the slab.
The concrete calculator takes any dimensions you like and hands back the same list.