How Much Concrete for a 12x16 Slab?
Concrete needed
2.61 cubic yards
A 12 by 16 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.
- Length12 ft
- Width16 ft
- Thickness4 in
- Waste allowance10 %
Concrete needed2.61 cubic yards
| Volume | 64 cu ft |
|---|---|
| Cubic yards before waste | 2.37 |
| Cubic yards with 10% waste | 2.61order to this number |
| Order in quarter yards | 2.75 cu yd |
| 60 lb bags, if bagging it | 157 |
| 80 lb bags, if bagging it | 118 |
The material list this produces
| Ready mix concrete, cubic yards | 2.75 |
|---|---|
| Rebar or mesh, sq ft of slab | 192 |
| Form lumber, linear ft | 56 |
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 | 2.61 cubic yards |
| 5 in | 3.26 cubic yards |
| 6 in | 3.91 cubic yards |
| 8 in | 5.21 cubic yards |
What else matters here
This is the standard bigger shed and the standard small patio, 192 square feet, and at four inches it needs about two and three quarter yards. That is one small truck, comfortably inside a minimum load, and it pours in well under an hour with three people.
Pour a rectangle this shape and the screed direction matters. Screed across the twelve foot dimension, not the sixteen, because a screed board spanning twelve feet with two people on it stays flat and one spanning sixteen bows in the middle. That bow becomes a low spot that holds water for the life of the slab.
If the slab will sit under a shed with a door on the long side, slope it. A quarter inch per foot away from the doorway is enough to keep rain off the threshold and is invisible to the eye.
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 cubic yards is a 12x16 slab?
2.37 cubic yards of volume at four inches, 2.61 with ten percent waste. You would order 2.75, since ready mix is sold in quarter yard steps.
Can I pour a 12x16 slab by myself?
Not comfortably. Two and three quarter yards is about 11,000 pounds of concrete, and a truck will want it off in half an hour. Three people is the practical minimum and four is better.
How much does a 12x16 concrete slab cost?
The concrete itself is the small part. Figure the yardage from this page, price it with your local supplier, then add forms, base gravel, mesh and labor. The job cost calculator on this site puts all of those in one place.
The concrete calculator takes any dimensions you like and hands back the same list.