A cubic yard of concrete takes about 45 bags of 80 pound mix, about 60 bags of 60 pound mix, or about 90 bags of 40 pound mix. Bag yields are typical values, so check the label on your brand.
The numbers
An 80 pound bag yields about 0.6 cubic feet of concrete. Divide 27 cubic feet by 0.6 and you get 45 bags. A 60 pound bag yields about 0.45 cubic feet, which is 60 bags per yard. A 40 pound bag yields about 0.3 cubic feet, which is 90 bags.
Because the yield depends on the brand and how much water you add, round up and buy a few extra bags.
Is it practical to mix this many bags?
Mixing 45 bags by hand or in a small mixer is a hard day of work. Most people switch to ready mix delivery above about 1 cubic yard. Ready mix also gives a more consistent product.
For small jobs such as setting a fence post or a small pad, bags are a good choice.
Weight
45 bags of 80 pound concrete is 3,600 pounds of dry mix before water. That is why people usually buy bags a few at a time.
Check against your slab
A 10 by 10 foot slab at 4 inches thick needs about 1.23 cubic yards. That is about 56 bags of 80 pound mix. A 5 by 5 foot pad at 4 inches needs about 0.31 cubic yards, or about 14 bags.
Concrete bags per cubic yard
| Bag weight | Typical yield (cubic feet) | Bags per cubic yard |
|---|---|---|
| 40 lb | 0.30 | 90 |
| 50 lb | 0.375 | 72 |
| 60 lb | 0.45 | 60 |
| 80 lb | 0.60 | 45 |
Frequently asked questions
How many 80 pound bags of concrete make a yard?
About 45 bags.
How many 60 pound bags make a yard?
About 60 bags.
How many 50 pound bags make a yard?
About 72 bags at 0.375 cubic feet each.
Is it cheaper to buy bags or ready mix?
Bags often cost more per yard once you need more than about 1 cubic yard, but delivery fees and minimums on small ready mix orders can change that.