Concrete calculator
Know the volume before the pour.
Estimate concrete volume and whole bags from slab dimensions, allowance, and the yield printed on your product label.
Clear math. Better decisions.
A worked example
A 10 × 10 ft slab at 4 inches thick needs 33.33 cubic feet before allowance. At 0.60 cubic feet of mixed yield per bag and 0% extra, round up to 56 bags.
Before you order
- Use mixed yield, not the dry bag's physical size or weight, for volume calculations.
- Thickened edges, piers, steps, and footings need separate estimates.
- Thickness, reinforcement, load capacity, permits, and mix selection are outside this calculator.
Reference: QUIKRETE: Mixing concrete and cement mixes.
Good questions.
Are all 80 lb bags equivalent?
No. Product formulation and stated yield matter. The starting 0.60 cubic-foot yield is an example from QUIKRETE Concrete Mix, not a guarantee for every product.
Does this tell me a safe slab thickness?
No. You supply the thickness. Structural design, local requirements, subgrade preparation, and reinforcement need their own assessment.
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