How Much Concrete for a 10x12 Slab?
Concrete needed
1.63 cubic yards
A 10 by 12 foot slab 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.
- Length10 ft
- Width12 ft
- Thickness4 in
- Waste allowance10 %
Concrete needed1.63 cubic yards
| Volume | 40 cu ft |
|---|---|
| Cubic yards before waste | 1.48 |
| Cubic yards with 10% waste | 1.63order to this number |
| Order in quarter yards | 1.75 cu yd |
| 60 lb bags, if bagging it | 98 |
| 80 lb bags, if bagging it | 74 |
The material list this produces
| Ready mix concrete, cubic yards | 1.75 |
|---|---|
| Rebar or mesh, sq ft of slab | 120 |
| Form lumber, linear ft | 44 |
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 | 1.63 cubic yards |
| 5 in | 2.04 cubic yards |
| 6 in | 2.44 cubic yards |
| 8 in | 3.26 cubic yards |
What else matters here
One and three quarter yards ordered. A 10 by 12 is a patio, a shed floor or a small parking pad, and at 120 square feet it is the size where reinforcement becomes a real question rather than an automatic no.
Wire mesh or fiber does not stop a slab cracking. Nothing does. What reinforcement does is hold the two sides of a crack together so it stays tight and does not step, which is the difference between a hairline you cannot catch a fingernail on and a lifted edge that catches a mower.
For a patio, fiber in the mix is usually enough and costs a few dollars a yard. For anything that will carry a vehicle, mesh or rebar properly supported in the middle third of the slab thickness is worth the trouble, and supported is the operative word: mesh left on the ground does nothing at all.
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 much concrete for a 10x12 slab?
About 1.63 cubic yards at 4 inches with waste, so order 1.75 yards.
Does a 10x12 patio need rebar?
Not necessarily. Fiber in the mix suits a patio. Anything carrying a vehicle is better with mesh or rebar, held up in the middle of the slab rather than lying on the ground.
Does reinforcement stop cracking?
No. It holds cracks tight and level once they happen, which is what keeps a hairline from becoming a lifted, tripping edge.
The concrete calculator takes any dimensions you like and hands back the same list.