80 lb vs 60 lb Concrete Bags — Yield Comparison
Concrete bag weight does not change the volume formula — it changes how many bags you carry and how many trips you make. An 80 lb bag yields about 0.60 ft³; a 60 lb bag about 0.45 ft³. For the same slab, 80 lb bags mean fewer bags but heavier lifts. Below is a direct yield comparison with example counts.
Last updated: June 25, 2026
Use the Concrete Bags Calculator →Steps
- Calculate project cubic feet — Use length × width × (thickness ÷ 12) for slabs, or π × r² × height for round columns, then add your waste factor.
- Divide by bag yield — 80 lb: ft³ ÷ 0.60. 60 lb: ft³ ÷ 0.45. 40 lb: ft³ ÷ 0.30. Round up to whole bags.
- Pick the size your store stocks — If only 60 lb bags are in stock, the math still works — expect about 33% more bags than 80 lb for the same volume.
Yield comparison
Typical US retail yields (verify your bag label): 40 lb ≈ 0.30 ft³, 60 lb ≈ 0.45 ft³, 80 lb ≈ 0.60 ft³.
Example: 40 ft³ net volume → 67 forty-pound bags, 89 sixty-pound bags, or 67 eighty-pound bags before rounding — always round up.
When to choose 80 lb bags
Fewer bags to open and mix on medium slabs — less packaging waste, fewer store trips if your vehicle handles the weight.
Downside: each bag is harder to lift; two-person teams are safer on large bag-count jobs.
When to choose 60 lb bags
Easier solo handling for footings, post holes, and patch work. Useful when your store does not stock 80 lb or when loading into a small car.
Trade-off: more bags to mix for the same volume — plan extra time on the job site.
Frequently asked questions
- How many 80 lb bags for a 10×10 × 4 in slab?
- About 62 bags with 10% waste (≈36.7 ft³ ÷ 0.60 ft³ per bag). The same pour needs about 82 sixty-pound bags.
- Is 80 lb or 60 lb concrete stronger?
- Strength comes from mix design (PSI on the label), not bag weight alone. Compare product labels — a 4000 PSI 60 lb bag is not weaker than a 3000 PSI 80 lb bag just because of weight.
- Can I mix bag sizes on one pour?
- Same PSI and mix type: yes in a pinch. Different brands or PSI ratings on one structural pour: avoid — inconsistent cure and strength.