Quick answer
Estimate concrete for a patio slab from measured patio dimensions, slab thickness and 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
A 16 × 12 ft patio at 4 in thick is about 64 ft³, or 2.37 yd³, before adding the ordering allowance.
Common uses
- Backyard patios
- Outdoor seating pads
- Grill pads
- Small courtyard slabs
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.
Concrete Patio Calculator FAQ
Should I subtract openings from a patio slab?
Subtract only areas that truly will not be poured. Small penetrations may not reduce the order meaningfully.
How do curves affect the estimate?
Break curved patios into measurable sections or use a conservative bounding shape, then refine with the actual layout.
Does this calculate reinforcement?
No. Reinforcement, joints, base preparation and structural details are separate project decisions.