Free Calculator Tool

Concrete Bag Calculator

Estimate concrete bag counts quickly for slabs, pads, post holes, and small pours.

Bag Count Formula

Total cubic feet divided by bag yield per bag size

Enter pour dimensions and select bag size to get required bag count with waste.

Length (ft) Pour length in feet Width (ft) Pour width in feet Thickness (in) 4 in for patios, 5-6 in for driveways Bag Size Waste (%)

Ready to calculate?

Enter values and run the calculator to see detailed results.

Clear answers for common estimation and planning questions.

How many cubic feet does one concrete bag cover?

Typical yields are about 0.6 cu ft for an 80 lb bag, 0.45 cu ft for 60 lb, and 0.3 cu ft for 40 lb bags.

Should I buy extra bags?

Yes. Add waste for uneven subgrade, spillage, and minor over-pour.

Can I use this for sonotube pours?

Yes. Use volume from your sonotube calculation, then convert to bag counts here.

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