Quick answer
Work out how much concrete a project needs by measuring its real dimensions, converting thickness correctly and adding a visible ordering allowance. Use the working RenoMetric calculator below for the actual estimate, then use this page to check assumptions, package rounding and project-specific considerations.
Open the working Concrete calculator
Formula
Worked planning example
For any rectangular pour, convert all dimensions to compatible units first, calculate raw volume, convert to cubic yards, then apply the allowance and purchase rounding.
Common uses
- Slabs
- Patios
- Driveways
- Footings and small pours
How to get a better estimate
Measure the actual project rather than relying on listing dimensions. For irregular spaces, split the surface into simple measurable sections and add the results. Use the exact product label for package coverage, yield, density or square-foot coverage whenever it is available.
Keep waste and package rounding as separate steps. Waste covers cuts, breakage, pattern matching and unavoidable offcuts. Package rounding reflects the fact that many materials are sold only in complete bags, boxes, bundles or cans.
Before you buy: this page is a planning guide, not a contractor quotation or structural design. Verify final quantities with the product manufacturer, supplier or installer when project conditions could materially change the result.
How Much Concrete Do I Need? FAQ
What measurements do I need?
For a rectangular slab, measure length, width and final concrete thickness. Other shapes may need to be split into multiple sections.
Why is thickness easy to get wrong?
Thickness is often measured in inches while length and width are in feet. Convert inches to feet before multiplying volume.
Should I order exactly what the formula says?
The geometric result is the starting point. Apply the allowance and supplier order increment appropriate to the real project.