Concrete calculator
Concrete bag calculator
Slab volume translated into a whole-bag purchase quantity using the stated bag yield.
Calculator result and formula
Concrete bags to order: 62 bags
Formula: L × W × D × (1 + waste) ÷ bag yield
Formula ID: CONC-BAG-001 · Version 1.0.0.
Inputs
- Pour length: Finished pour length Default: 10.
- Pour width: Finished pour width Default: 10.
- Concrete depth: Specified finished pour depth Default: 4.
- Bag yield: Yield stated on the selected bag, in cubic feet Default: 0.6.
- Waste factor: Allowance for spill and site conditions Default: 10.
How this calculator works
This calculator converts a rectangular pour into whole bags using the actual yield published for the selected bagged-concrete product.
- Measure the finished pour length, width and depth.
- Enter the yield stated on the selected bag rather than assuming every bag performs the same.
- Apply the visible allowance before whole-bag rounding.
Worked example: Example: a 10 ft × 10 ft pour at 4 in depth contains 33.33 ft³. With 10% waste and a 0.60 ft³ bag yield, the purchase quantity rounds to 62 bags.
Assumptions and limitations
- Bag yield is the user-entered value from the exact selected product label.
- Waste is applied before whole-bag rounding.
- This tool does not select mix strength or installation method.
Common questions
- Can I use any bag yield?
- Use the yield shown by the exact product manufacturer; bag size alone does not guarantee the same yield.
- When should I use ready-mix instead?
- Supplier delivery suitability depends on job scale, access, timing and local availability; obtain a supplier quote.
Reference notes
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