How many bags of concrete do I need?
Volume in cubic feet = area in square feet x thickness in feet, so a thickness in inches is divided by 12. [1] Bags = the volume with your extra, divided by the yield of one bag, rounded up to a whole bag.
QUIKRETE says an 80 lb bag of its Concrete Mix yields approximately 0.60 cubic feet, and Sakrete's page for its 80 lb mix says .6 cubic feet. [3] [5] The yield changes with the bag size, so pick the size you will buy and check the number printed on the bag.
NRMCA says to order about 4% to 10% more ready mixed concrete than a calculation of the plan dimensions gives. [2] We found no source for an extra on bagged concrete, so this calculator starts at the same 10% and lets you change it.
Worked example
A 10 ft x 10 ft slab, 4 in thick: 10 x 10 x 4 / 12 = 33.33 cubic feet. Adding 10% extra gives 36.67 cubic feet. One 80 lb bag yields 0.60 cubic feet, so 36.67 / 0.60 = 61.11, and you order 62 bags.
How many bags of concrete are in a cubic yard?
A cubic yard is 27 cubic feet, so the bags in a yard are 27 divided by the yield of one bag, at the yields QUIKRETE gives for each size. [3]
| Bag size | Yield (ft³) | Bags in a cubic yard |
|---|---|---|
| 80 lb | 0.600 | 45 |
| 60 lb | 0.450 | 60 |
| 50 lb | 0.375 | 72 |
| 40 lb | 0.300 | 90 |
How many 80 lb bags of concrete are in a yard?
At 0.60 cubic feet a bag, 27 / 0.60 = 45 bags of 80 lb.
How many 60 lb bags of concrete are in a yard?
At 0.45 cubic feet a bag, 27 / 0.45 = 60 bags of 60 lb.
How much does a bag of concrete cover?
The cubic feet in a bag, spread over a thickness. Square feet covered = yield x 12 / thickness in inches.
| Bag size | Yield (ft³) | At 2 in (ft²) | At 4 in (ft²) | At 6 in (ft²) |
|---|---|---|---|---|
| 80 lb | 0.600 | 3.6 | 1.8 | 1.2 |
| 60 lb | 0.450 | 2.7 | 1.35 | 0.9 |
| 50 lb | 0.375 | 2.25 | 1.13 | 0.75 |
| 40 lb | 0.300 | 1.8 | 0.9 | 0.6 |
How many bags of concrete are on a pallet?
QUIKRETE's page for its Concrete Mix 1101 lists 80 bags of 40 lb, 56 bags of 60 lb and 42 bags of 80 lb on a pallet. [4] Sakrete's page for its 80 lb mix lists 42 bags on a pallet. [5] We found no pallet count for the 50 lb bag, and counts vary by maker, so check the one you buy.
| Bag size | Bags on a pallet | Weight of the bags (lb) |
|---|---|---|
| 40 lb | 80 | 3,200 |
| 60 lb | 56 | 3,360 |
| 80 lb | 42 | 3,360 |
The last column is the bag size times the count. It leaves out the pallet itself.
How much does a bag of concrete weigh?
Bag sizes
QUIKRETE's Concrete Mix comes in bags of 40, 50, 60 and 80 lb, and 90 lb in some regions. [3]
How many bags for a 10x10 or 12x12 slab?
Square slabs, with the starting 10% extra, in 80 lb and 60 lb bags. The 4 in thickness is only an example.
| Slab | Area (ft²) | 80 lb bags | 60 lb bags |
|---|---|---|---|
| 10 x 10 ft | 100 | 62 | 82 |
| 12 x 12 ft | 144 | 88 | 118 |
| 16 x 16 ft | 256 | 157 | 209 |
| 20 x 20 ft | 400 | 245 | 326 |
How much water per bag of concrete?
QUIKRETE's data sheet gives a starting amount of water for each bag size and the most it expects, in pints. [3] It says to add more water if the material is too difficult to mix, until a workable mix is obtained. The label of your own mix comes first.
| Bag size | Starting (pt) | Most expected (pt) |
|---|---|---|
| 40 lb | 3 | 4 1/2 |
| 50 lb | 3 1/2 | 5 1/2 |
| 60 lb | 4 | 7 |
| 80 lb | 6 | 9 |
How much do bags of concrete cost?
We state no price. Ask your supplier what one bag costs, then type it into the optional Price per bag box above for the total. The site does not store the prices you type.
Common mistakes and limits
- Using the wrong bag size. An 80 lb bag and a 60 lb bag yield different amounts, so pick the size you will buy.
- Buying exactly the bags. NRMCA says to order about 4% to 10% more ready mixed concrete than the plan dimensions give. [2]
- Buying cement when you want concrete mix. NRMCA calls it a common misunderstanding that cement and concrete are one and the same. [2]
- Trusting the count without checking the bag. The yield on your own bag comes first, so compare it with the table.
- What this tool does not cover: the strength of the mix you buy, how to mix it, forms and curing.
Frequently asked questions
Is cement the same as concrete?
No. NRMCA calls it a common misunderstanding that cement and concrete are one and the same. Cement is the powdered ingredient that binds the aggregates together into concrete. [2]
How many bags can a mixer hold?
QUIKRETE says to allow at least 1 cubic foot of mixer capacity for each 80 lb bag mixed at one time. A mixer of 3 cubic feet, for example, holds 3 bags of 80 lb at a time by that rule. [3]
How long can bagged concrete be stored?
We found no source we can cite for the storage life of bagged concrete or for storing it outside. Check the bag for the maker's advice, and ask the store.
My bag shows a different yield. What do I do?
Use the yield on your bag. Open Your bag and price (optional) and type it into Yield printed on your bag, and the bag count changes at once.
How many bags of concrete are in a cubic yard?
A cubic yard is 27 cubic feet. At QUIKRETE's yields that is 45 bags of 80 lb, 60 of 60 lb, 72 of 50 lb and 90 of 40 lb. [3]
Sources and references
- National Institute of Standards and Technology (NIST). NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically (SP 811, accessed November 2026). Used for: the inch and foot relationship and the 27 cubic feet in a cubic yard.
- National Ready Mixed Concrete Association (NRMCA). CIP 31, Ordering Ready Mixed Concrete (Concrete in Practice, PDF dated 2006, accessed November 2026). Used for: the 4% to 10% extra, and that cement and concrete are not the same thing.
- The QUIKRETE Companies. Data Sheet, Concrete Mix, Product No. 1101-40, -50, -60, -80, -90 (revised October 2022, accessed November 2026). Used for: the yield of each bag size, the water per bag, and the mixer size for a bag.
- The QUIKRETE Companies. QUIKRETE Product 1101 Concrete Mix, page for Lowe's (accessed November 2026). Used for: the number of bags on a pallet.
- Oldcastle APG (Sakrete). Sakrete High-Strength Concrete Mix 80 lb Gray (accessed November 2026). Used for: a second maker's yield and pallet count for an 80 lb bag.
How we use sources: methodology.
Estimates only. Confirm quantities with your supplier. See the disclaimer. Found a wrong result? Report an error.