/// Answer-first planning notes
How many cubic yards and bags of concrete do I need?
| Planning input | Calculation role | Check before ordering |
|---|---|---|
| 40 lb | Approximately 0.30 ft³ | QUIKRETE No. 1101-40 onlySources: The QUIKRETE Companies, LLC |
| 50 lb | Approximately 0.375 ft³ | QUIKRETE No. 1101-50 onlySources: The QUIKRETE Companies, LLC |
| 60 lb | Approximately 0.45 ft³ | QUIKRETE No. 1101-60 onlySources: The QUIKRETE Companies, LLC |
| 80 lb | Approximately 0.60 ft³ | QUIKRETE No. 1101-80 onlySources: The QUIKRETE Companies, LLC |
These published yields apply only to the named QUIKRETE Concrete Mix No. 1101 packages. They are not generic bag-yield assumptions for other brands or products.
Evidence: The QUIKRETE Companies, LLC · The QUIKRETE Companies, LLC · The QUIKRETE Companies, LLC · The QUIKRETE Companies, LLC/// Formula & field notes
How this concrete estimate works
FormulaRectangular volume = length × width × depth. Circular volume = π × (diameter ÷ 2)² × depth. Adjusted volume = base volume × (1 + waste %).
Worked example
A 10 ft × 10 ft slab at 4 in deep equals 1.2346 yd³. With 10% waste it becomes 1.3580 yd³, or 62 bags when each 80 lb bag yields about 0.60 ft³.
/// Source trail
Data & assumptions
Every source has a declared scope. A reference can support a conversion or product assumption without turning this estimate into a supplier quote.
Exact international-foot to meter conversion; U.S. survey-foot conversion is explicitly outside this claim.
Independent confirmation that one international foot equals exactly 0.3048 meters; U.S. survey-foot conversion remains distinct.
Approximate 0.3 ft³ yield for the 40 lb QUIKRETE Concrete Mix No. 1101-40 package only; not a generic bag-yield assumption.
The QUIKRETE Companies, LLC · Primary evidenceQUIKRETE Concrete Mix No. 1101-50 product yieldApproximate 0.375 ft³ yield for the 50 lb QUIKRETE Concrete Mix No. 1101-50 package only; not a generic bag-yield assumption.
The QUIKRETE Companies, LLC · Primary evidenceQUIKRETE Concrete Mix No. 1101-60 product yieldApproximate 0.45 ft³ yield for the 60 lb QUIKRETE Concrete Mix No. 1101-60 package only; not a generic bag-yield assumption.
The QUIKRETE Companies, LLC · Primary evidenceQUIKRETE Concrete Mix No. 1101-80 product yieldApproximate 0.6 ft³ yield for the 80 lb QUIKRETE Concrete Mix No. 1101-80 package only; not a generic bag-yield assumption.
/// Common questions
Concrete calculator FAQ
How much extra concrete should I order?
Use a project-specific allowance for irregular excavation, compaction, spillage, cuts, and supplier minimums. ProjectQty starts at zero instead of guessing; enter the allowance your plan or supplier supports, then confirm the final cubic yards or bags.
Is the result a supplier quote?
No. ProjectQty calculates quantities from your dimensions and assumptions. Prices are optional user inputs, not live local quotes, and delivery, taxes, minimum loads, and labor are not included unless you add them separately.
Can I use metric measurements?
Yes. Switch to Metric before entering measurements. ProjectQty normalizes the geometry internally and shows the most useful ordering units for the selected material.