Concrete Calculator for Patios
Estimate concrete for a patio slab.
A concrete patio slab is typically 4 inches thick over a compacted gravel base. The calculator starts at 4 inches and shows both cubic yards and the number of 80 lb bags, so you can compare bags against ready-mix.
Concrete Calculator
Estimate how much you need — and the cost.
- cubic feet 33.33
- cubic meters 0.944
- tons (US) 2.5
- tonnes 2.27
Tip: For anything bigger than about half a cubic yard, ready-mix delivery beats mixing bags by hand.
How it's calculated
1 cubic yard = 27 cu ft, covering about 81 sq ft at 4 in / 54 sq ft at 6 in; an 80 lb pre-mix bag yields about 0.6 cu ft (about 45 bags per cubic yard).
See the full Concrete Calculator for the complete how-to, unit conversions, and data sources.
Concrete Calculator for Patios FAQ
How thick should a concrete patio be?
4 inches is standard for a patio over a solid base. Step up to 5–6 inches if vehicles will ever sit on it.
How much concrete for a patio?
A 200 sq ft patio at 4 inches needs about 2.5 cubic yards, or roughly 110 of the 80 lb bags.