How Much Concrete for a 40x60 Slab?
Concrete needed
48.89 cubic yards
A 40 by 60 foot slab at six 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.
- Length40 ft
- Width60 ft
- Thickness6 in
- Waste allowance10 %
Concrete needed48.89 cubic yards
| Volume | 1,200 cu ft |
|---|---|
| Cubic yards before waste | 44.44 |
| Cubic yards with 10% waste | 48.89order to this number |
| Order in quarter yards | 49 cu yd |
| 60 lb bags, if bagging it | 2,934 |
| 80 lb bags, if bagging it | 2,200 |
The material list this produces
| Ready mix concrete, cubic yards | 49 |
|---|---|
| Rebar or mesh, sq ft of slab | 2,400 |
| Form lumber, linear ft | 200 |
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 | 32.59 cubic yards |
| 5 in | 40.74 cubic yards |
| 6 in | 48.89 cubic yards |
| 8 in | 65.19 cubic yards |
What else matters here
Twenty four hundred square feet is the common pole barn and small commercial shop footprint. At six inches it is nearly fifty yards, five or six trucks, and it is the point at which a slab stops being a homeowner project and becomes a concrete job with a crew, a pump or a laser screed, and a finishing plan written down.
Nobody pours fifty yards in one monolithic piece by hand. It goes in strips, usually the width of the screed setup, with construction joints between them and dowels across those joints so the strips deflect together under load. Getting that layout right before the first truck is most of the work.
Joint spacing on a six inch slab is twelve to fifteen feet, so a 40 by 60 wants roughly a 12 by 15 grid, sixteen panels. Cut them early with a soft cut saw, within hours rather than days, because a slab this large generates enough shrinkage stress to find its own cracks overnight.
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 yards of concrete is a 40x60 slab?
44.44 cubic yards at six inches, 48.89 once a ten percent waste allowance is added. At four inches it is 32.6 with waste.
How many trucks for a 40x60 slab?
Five to six at nine or ten yards each. At that volume most suppliers will want the order placed days ahead and will ask about your pump, pour sequence and finishing crew.
Can a 40x60 slab be poured in sections?
Yes, and it normally is. Pour in strips with proper construction joints and dowel bars across them. What you must not do is let a pour that was meant to be continuous accidentally become two, which leaves a cold joint with nothing across it.
The concrete calculator takes any dimensions you like and hands back the same list.