# How Many Bags of Concrete Are in a Cubic Yard?

_Published October 4, 2026_

**In short:** A cubic yard of concrete takes 45 bags of 80-lb mix, 60 bags of 60-lb mix or 90 bags of 40-lb mix, because a yard is 27 cubic feet and an 80-lb bag yields about 0.60. A 10 by 10 foot slab at 4 inches needs 1.23 yards, or 56 bags.

## The short answer

Concrete is sold two ways: by the cubic yard from a ready-mix truck, and by the bag as dry mix you blend with water. To compare them you need one conversion. A cubic yard holds 27 cubic feet, and each bag yields a known volume once mixed. Divide 27 by the bag's yield and you have the bag count.

| Bag size | Yield per bag | Bags per cubic yard | Bag weight total |
| --- | --- | --- | --- |
| 80 lb | 0.60 cu ft | 45 | 3,600 lb |
| 60 lb | 0.45 cu ft | 60 | 3,600 lb |
| 40 lb | 0.30 cu ft | 90 | 3,600 lb |

The yields are the values printed on common bagged mixes, such as the roughly 0.60 cubic feet QUIKRETE lists for an 80-lb bag of its standard concrete mix. Other brands and mixes can differ a little, so read the yield on the bag you actually buy and divide 27 by it.

## The formula

```
bags = cubic yards × 27 ÷ yield per bag (cu ft)
```

For a full yard of 80-lb mix that is 27 ÷ 0.60 = 45 bags. The weight column above is just 45 × 80 lb, which is 3,600 lb of dry mix before water. That is a lot of lifting and mixing, and it is the main reason people switch to a truck for larger jobs.

## Bags needed for common slab sizes

Find the slab volume first (length × width × thickness in feet, divided by 27 for yards), then divide the cubic feet by the bag yield. The table below is for a 4-inch slab with no waste allowance, using 80-lb bags.

| Slab size | Cubic yards | 80-lb bags |
| --- | --- | --- |
| 8 × 8 ft | 0.79 | 36 |
| 10 × 10 ft | 1.23 | 56 |
| 12 × 12 ft | 1.78 | 80 |
| 12 × 16 ft | 2.37 | 107 |
| 20 × 20 ft | 4.94 | 223 |

Use the [concrete calculator](../../concrete-calculator/) for any other size or for footings, walls, columns and steps. It also returns bag counts for all three bag sizes. If you already have a volume in cubic feet or inches, the [cubic yard calculator](../../cubic-yard-calculator/) converts it.

## Worked example: a 10 × 10 patio

A patio slab 10 ft by 10 ft and 4 inches thick has 10 × 10 × (4 ÷ 12) = 33.3 cubic feet, which is 1.23 cubic yards. Bags are bought whole, so with no allowance you round 33.3 ÷ 0.60 = 55.6 up to 56 bags.

Now add a 10% waste allowance, which is a common planning figure. The volume becomes about 36.7 cubic feet, or 1.36 cubic yards, and the bag count becomes 62 bags of 80-lb mix. Concrete Network suggests ordering an extra 10 to 15 percent to cover spillage and uneven subgrade, so treat 10% as the low end for a patio poured on a hand-dug base.

## Bags or ready-mix?

The break-even depends on your labor and local prices, but the arithmetic is easy to run yourself. Suppose an 80-lb bag costs $6 where you live (check your store, this is only an example). A full yard in bags is 45 × $6 = $270. If a local supplier quotes a yard of ready-mix at, say, $165 plus a delivery or short-load fee, the truck can be cheaper before you count your time. Ready-mix suppliers often set a minimum order, so call two or three and ask for the delivered price on your exact volume.

- **Under about 1 cubic yard:** bags are usually the practical choice, such as post holes, a small pad or a few footings.

- **1 to 2 yards:** compare both. A short-load fee on a truck can make bags competitive.

- **Over 2 yards:** hand mixing 90 or more bags is slow, and the batches vary. Ready-mix usually wins on speed and consistency.

## Common mistakes

- **Using one bag count for every brand.** Yield changes with bag size and product. Divide 27 by the number on your bag.

- **Forgetting the waste allowance.** Running out mid-pour risks a cold joint where fresh and partly set concrete meet.

- **Mixing up units.** Thickness is in inches, length and width in feet. Convert inches to feet before multiplying, or the answer is 12 times off.

- **Counting the bag weight as the concrete weight.** Mixed concrete weighs about 4,000 pounds per cubic yard according to Concrete Network, because water is added to the dry mix.

- **Mixing too many bags by hand.** A pour you cannot finish before the surface stiffens will look and perform worse. Split large pours into sections with forms, or bring in help or a truck.

## What else to order or consider

A slab needs a compacted base, forms, and often wire mesh or rebar for crack control. The [gravel calculator](../../gravel-calculator/) gives tons for the base from the same dimensions. Wear eye protection and a dust mask when pouring dry mix, since cement dust irritates skin and lungs. For anything structural, such as a footing that carries a wall or deck, follow your local building code and ask the building department or an engineer what applies.

## Frequently asked questions

### How many 80-lb bags of concrete make 1 cubic yard?

It takes 45 bags of 80-lb mix, because a cubic yard is 27 cubic feet and each bag yields about 0.60 cubic feet. Check the yield printed on your bag, since it varies by product.

### How many bags of concrete do I need for a 10 x 10 slab?

A 10 by 10 foot slab at 4 inches thick is 1.23 cubic yards, which is 56 bags of 80-lb mix with no waste allowance. With 10% extra, plan on 62 bags.

### How many 60-lb or 40-lb bags are in a yard?

A cubic yard takes 60 bags of 60-lb mix (0.45 cubic feet each) or 90 bags of 40-lb mix (0.30 cubic feet each).

## Sources and further reading

- [Concrete Calculator: how much do I need? (bags and yards)](https://www.concretenetwork.com/concrete/howmuch/calculator.htm) — The Concrete Network
- [How Many Square Feet in a Yard of Concrete?](https://www.concretenetwork.com/concrete/howmuch/square-feet-in-a-yard.html) — The Concrete Network
- [Concrete Mix, Product No. 1101 (data sheet)](https://www.quikrete.com/pdfs/data_sheet-concrete%20mix%201101.pdf) — QUIKRETE