How much concrete do I need for a patio?

Patios are usually simple slabs, so the estimate comes down to area, thickness, and a small waste allowance.

Best for

Worked example

A 5 m by 4 m patio at 0.12 m thickness

Patio slabs are typically shallow, but a waste allowance still helps if the finish or edge profile is awkward.

Example

5 m × 4 m × 0.12 m = 2.4 m3. With 7 percent waste, the adjusted order volume is 2.57 m3.

Formula

Volume = length × width × thickness

Adjusted volume = volume × (1 + waste / 100)

How to use it

Use outer dimensions for a rectangular patio and keep thickness consistent across the slab.

If the patio slopes or steps, split it into separate rectangles and add the results.

Round up if the pour is awkward or if the finish layer is likely to consume extra material.

Use the slab calculator if you want a generic rectangular slab page.

Open the main calculator for all concrete shapes.

Switch to the foundation page if the job is deeper or structural.