A cubic yard of concrete takes 45 bags of 80 lb mix, 60 bags of 60 lb, or 90 bags of 40 lb. Add about 10% for spillage and uneven ground, which makes it 50 bags of the 80 lb size.
In bags, that yard costs about $299. The same yard from a ready-mix truck averages $185 before delivery fees, so bags only win on small pours.
Bags of concrete per cubic yard, by bag size
A cubic yard is 27 cubic feet. Each bag makes a fixed amount of concrete once it is mixed, so the count is just 27 divided by the bag's yield. Quikrete's data sheet for its standard concrete mix gives the yields below.
| Bag | Yield | Bags per yard | With 10% extra | Dry weight to haul |
|---|---|---|---|---|
| 80 lb | 0.60 cu ft | 45 | 50 | 3,600 lb |
| 60 lb | 0.45 cu ft | 60 | 66 | 3,600 lb |
| 40 lb | 0.30 cu ft | 90 | 100 | 3,600 lb |
The bag size changes how many trips you make, not how much concrete you get. Every row above hauls about 3,600 pounds of dry mix home for one yard. Check the payload rating on your truck's door sticker before loading a full yard into it.
How many bags for common pours
All at 4 inches thick, with 10% extra already included.
| Pour | Concrete | 80 lb bags | 60 lb bags |
|---|---|---|---|
| 4x4 landing | 5.3 cu ft (0.20 yd) | 10 | 14 |
| 3x10 walkway | 10.0 cu ft (0.37 yd) | 19 | 25 |
| 8x8 pad | 21.3 cu ft (0.79 yd) | 40 | 53 |
| 10x10 shed pad | 33.3 cu ft (1.23 yd) | 62 | 82 |
| 12x12 patio | 48.0 cu ft (1.78 yd) | 89 | 118 |
Going thicker than 4 inches raises every number in proportion: a 6-inch slab takes half again as many bags. The slab thickness guide covers which thickness each job needs.
How to work out bags for any slab
- Multiply length by width in feet to get square feet.
- Multiply by the thickness in inches, then divide by 12. That is cubic feet.
- Divide by the bag yield: 0.6 for 80 lb, 0.45 for 60 lb.
- Multiply by 1.1 for the extra 10%, and round up.
Sakrete offers a shortcut for 4-inch slabs that already includes the 10%: multiply the square footage by 0.6 to get the number of 80 lb bags. A 9x9 slab is 81 square feet, so about 49 bags. The Concrete Calculator does the same math for slabs, footings and round columns, and gives bag counts alongside cubic yards.
Bags or a ready-mix truck?
Per yard, bags cost more. At $6.65 for an 80 lb bag, a yard of bagged concrete comes to about $299, against a ready-mix average of $185 per yard. Bags still win on small jobs because a truck brings minimum charges and short-load fees that can cost more than the concrete.
On the four supplier price sheets we track, the truck becomes cheaper somewhere between 1 and 3yards. Below that, buy bags. Above it, call a plant. The full comparison, with each supplier's fees, is on the concrete price per yard page.
Labor matters too. A yard is 45 bags to lift, open and mix, each one adding water and time. Count that in when the numbers come out close, because the price gap does not include your afternoon.
Sources and how we checked
- Bag yields: Quikrete Concrete Mix (1101) data sheet.
- 10% extra and the 0.6 shortcut: Sakrete, Estimating Bagged Concrete Jobs.
- Bag price: $6.65 for an 80 lb bag, as quoted by LawnStarter. Store prices vary by region and brand.
- Ready-mix price and supplier fee sheets: CalcRafter's concrete price index, method on How We Calculate and Price.
Every count and dollar figure here is calculated when the site is built, from the same constants the price index uses, so this page updates when those do. Spot something wrong? Email soleman@calcrafter.com.
Skip the arithmetic
Enter your own dimensions and get the exact figure instead of working from averages.
Open the Concrete CalculatorFrequently asked questions
45 bags of 80 lb mix, 60 bags of 60 lb, or 90 bags of 40 lb. An 80 lb bag yields about 0.6 cubic feet and a cubic yard is 27, so 27 divided by 0.6 is 45. Buy about 10% extra, which puts an 80 lb order at 50 bags.
About 1.8 square feet at 4 inches thick, or roughly 3.6 square feet at 2 inches. The bag makes about 0.6 cubic feet of concrete, so the thicker the slab, the less ground each bag covers.
62 bags for a 10x10 slab 4 inches thick, including 10% extra. The slab is 33.3 cubic feet, or 1.23 cubic yards.
For small jobs, bags. A yard in 80 lb bags costs about $299 at $6.65 a bag, against about $185 a yard for ready-mix before delivery fees. Those fees are why bags win on small pours. On the four supplier price sheets we track, ready-mix becomes the cheaper option somewhere between 1 and 3 yards.
60. A 60 lb bag yields about 0.45 cubic feet, and 27 divided by 0.45 is 60. That is 15 more bags to lift and mix than with 80 lb bags, for the same concrete.
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