How many bags of concrete do I need?
Divide the required concrete volume by the yield printed on the bag, then round up. One cubic yard is 27 cubic feet, equal to about 60 60-lb bags or 45 80-lb bags before adding extra material.
10 ft³ with 10% extra
11.0 ft³ of adjusted concrete volume
How many bags of concrete are in one cubic yard?
One cubic yard contains 27 cubic feet. Using typical published yields, that equals about 90 40-lb bags, 72 50-lb bags, 60 60-lb bags, 45 80-lb bags, or 40 90-lb bags. These counts are for exactly one cubic yard before adding extra material for grade variation, spillage, or form leakage.
For a smaller project, calculate the project volume in cubic feet and use the Concrete Bag Calculator to round the result up to whole bags.
The calculation
Start with 10 cubic feet and add 10% extra:
Bag weight alone does not determine volume. Use the stated yield for the exact mix because specialty products can differ.
Typical yield for one bag
| Bag size | Approximate yield | Bags per exact cubic yard |
|---|---|---|
| 40 lb | 0.30 ft³ | 90 |
| 50 lb | 0.375 ft³ | 72 |
| 60 lb | 0.45 ft³ | 60 |
| 80 lb | 0.60 ft³ | 45 |
| 90 lb | 0.675 ft³ | 40 |
These are published QUIKRETE Concrete Mix yields. Check the data sheet or package for the product you are buying.
Measure the project volume first
- Rectangular work: multiply length × width × depth in consistent units.
- Round holes: multiply π × radius² × depth.
- Convert inches: divide inches by 12 before multiplying dimensions in feet.
- Add the sections: calculate steps, footings, or holes separately, then total them.
- Apply extra last: add a deliberate percentage after calculating the exact volume.
When bagged concrete makes sense
Bags are convenient for small placements, repairs, and sites that are hard for a ready-mix truck to reach. Larger pours can require many bags, repeated mixing, and careful placement timing. Compare labor, mixer capacity, delivery minimums, and the need to place the concrete continuously before choosing a supply method.
Frequently asked questions
Should I round the bag count up?
Yes. Concrete is sold in whole bags, and rounding down leaves less volume than the calculation requires.
How much extra concrete should I include?
Five to ten percent is a common planning range, but the right allowance depends on excavation accuracy, subgrade variation, form leakage, and the consequences of running short.
Can unused bags be saved?
Only if they remain dry and within the manufacturer’s storage guidance. Moisture can cause cement products to harden inside the bag.