How the calculation works
Bags = round up [(volume in yd³ × 27 × allowance factor) ÷ finished ft³ per bag].
A worked example
One cubic yard requires 45 bags at 0.60 ft³ per bag before waste. A 10% allowance raises the purchase to 50 bags.
How many 80 lb bags make one cubic yard?
At a finished yield of 0.60 cubic feet per bag, one cubic yard needs 45 bags before allowance. A selected 10% allowance makes it 50 whole bags. Check the yield for the specific product you buy.
Can I use dry bag weight to calculate yield?
Use the manufacturer’s finished-volume yield. Dry bag weight is not the volume of mixed concrete. Products with the same bag weight can have different published yields.
What to check before using the result
- Dry bag weight is not finished concrete volume.
- Yields differ by product. A 90 lb Sakrete bag does not necessarily match a 90 lb QUIKRETE bag.
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References & product information
Method prepared 2026-10-21. See our calculation and editorial methods. Spotted a problem? Tell us about it.