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.

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 · Published · Last reviewed Aug 26, 2026.

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 mistakes to avoid

Confirm the measurement basis and units before using the result.
Keep waste or allowance visible and adjust it for the actual job conditions.
Confirm supplier packaging, delivery increments, specifications, and final site requirements before ordering.

Calculator disclaimer

This planning calculator does not determine structural design, code compliance, installation requirements, or guaranteed pricing. Confirm final requirements with the appropriate responsible professional, authority, manufacturer, and supplier.

Formula review and sources

Internal QA complete · independent external review pending · 1 source reference.

Sakrete: estimating bagged concrete jobs

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