Patio vs Driveway Concrete Thickness

Walkway and patio slabs people only walk on are often planned around 4 inches (100 mm). Shed bases may be similar if loads are light. Driveways and garage slabs that take cars are typically thicker and may need reinforcement — confirm with local practice and code.

These are planning norms, not a design specification. Poor soil or heavy loads change the answer.

Volume is area × thickness. Increasing thickness from 4 to 6 inches raises concrete volume by half for the same footprint. That is why two quotes with different thicknesses cannot be compared on price alone.

Enter the thickness your contractor proposes into the Concrete Calculator so the material line matches the structural assumption.

Compacted gravel under the slab supports the concrete and helps drainage. Estimate that layer with the Gravel Calculator using the sub-base depth in the specification — it is not included in the concrete volume.

Skipping sub-base on soft ground is a common DIY failure mode that no calculator can fix after the pour.

Mesh, rebar, fibre, and control joints are specification choices. They affect labour and materials but not the basic cubic volume of concrete.

Ask quotes to state thickness, strength mix, reinforcement, and finish separately so you can compare like with like.