Formula or decision rule
length × width × thickness × (1 + allowance ÷ 100) ÷ selected bag yield- Convert all dimensions to feet before computing cubic feet.
- Bag yield is approximate, so the unrounded result is planning math.
- The final purchase count always rounds up.
QUIKRETE Concrete Mix No. 1101 stated approximate yield
| Bag | Mass | Yield |
|---|---|---|
| 40 lb | 18.1 kg | 0.30 ft³ / 8.5 L |
| 60 lb | 27.2 kg | 0.45 ft³ / 12.7 L |
| 80 lb | 36.2 kg | 0.60 ft³ / 17 L |
Work through the project
Confirm finished dimensions
Measure the inside dimensions of the planned form and use the actual uniform placement thickness.
Choose the bag carried locally
Select only the bag size shown on the current product sheet and match it at purchase.
Round once
Keep full volume precision through the division, then round the final bag count upward.
Safety and scope
- Confirm base, reinforcement, joint, drainage, frost, and permit requirements locally.
- Wet cement is caustic; follow the product safety data and use appropriate skin and eye protection.
Sources and scope
Source links reviewed July 16, 2026. A review date is not the document's publication date.
- QUIKRETE: Concrete Mix No. 1101 Technical Data SheetNorth America · manufacturer data sheet
Bag counts are based on stated approximate yield and must be rounded up to whole bags.
- National Institute of Standards and Technology: NIST Guide to the SI, Appendix B — Conversion FactorsUnited States · government standard
Code retains exact defining constants where NIST identifies an exact relationship.