Things you may need
A quick list for the aisle. You may already own half of it.
- Concrete mix
- Mixing tub or mixer
- Trowel
- Float
- Gloves
- Safety glasses
- Level
- Screed board
Concrete Calculator
Estimate concrete volume and bags for a simple slab or pad using length, width, thickness, bag yield, overage, and price.
Before you buy Measure once more, check the product label, then use this as your shopping-list number.
Enter your project details
Use the defaults for a quick estimate, or adjust the advanced fields to match the product you plan to buy.
How the estimate works
The calculator uses your measurements plus ordinary unit conversions. Editable fields handle the parts that change by product: waste, coverage, bag yield, box coverage, or material density.
The buy recommendation rounds up because stores do not sell half gallons, partial boxes, or a fraction of a bag.
Beginner notes
- Use the actual yield printed on the concrete bag.
- Add a small overage so you do not run short during the pour.
- Thickness, base prep, reinforcement, and curing matter for real-world performance.
Planning estimate only
Actual material needs change with product, installation method, surface condition, layout, waste, and local requirements. For structural, permit, drainage, electrical, plumbing, or load-bearing work, get qualified local guidance.
Questions people usually ask
How many cubic feet does an 80 lb bag make?
Many 80 lb concrete bags yield about 0.60 cubic feet, but always check the bag label.
Is this structural advice?
No. This calculator estimates material quantity only. Structural, load-bearing, permit, and code questions need qualified local guidance.
Should I add extra concrete?
A 5% to 10% planning overage is common for small slab estimates.
Helpful next reads
Concrete
How many bags of concrete do I need?
Estimate bags for small slabs and pads, understand bag yield, and know when the calculator is not enough.
Accuracy
How accurate are these calculators?
Where estimates work, where they fail, and when to check the product label instead.
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