Patio Size Calculator
Enter the length and width of your patio, choose a paver or slab size and set the sub-base and bedding depths. The calculator counts the pavers with waste and works out the tonnes of stone and sand, how deep to dig and how much soil to remove.
- Pavers needed
- Sub-base and sand
- Dig depth
Use 100 mm of sub-base for a foot traffic patio on firm ground, and 150 mm on clay or soft soil.
A patio is mostly what you cannot see. Under the slabs sits a bed of sand or grit and a compacted layer of crushed stone. A 4 × 3 m patio in 600 × 600 mm slabs needs about 34 slabs, 2.5 tonnes of sub-base at 100 mm and 0.6 tonnes of bedding at 30 mm, and a dig about 155 mm deep.
Slabs for common patios
600 × 600 mm slabs with 10 mm joints. Search for a size.
| Patio (m) | Area (m²) | 600 × 600 slabs | 200 × 100 pavers |
|---|---|---|---|
| 2 × 2 | 4 | 12 | 204 |
| 3 × 2 | 6 | 17 | 306 |
| 3 × 3 | 9 | 26 | 459 |
| 4 × 3 | 12 | 34 | 612 |
| 4 × 4 | 16 | 46 | 816 |
| 5 × 4 | 20 | 57 | 1020 |
| 6 × 4 | 24 | 68 | 1224 |
| 6 × 5 | 30 | 85 | 1529 |
5% waste added.
Patio size and slabs
Square patio, 600 mm slabs. Slide the side length.
The plan shows the slabs laid in a staggered pattern.
How to work out patio materials
From the ground up. Step through it.
Measure
Length × width.
Set the patio at least 150 mm below the damp-proof course of the house and slope it away.
Slabs, porcelain or block pavers
Patio surfaces. Compare them.
Large and quick.
Hard wearing.
Small units.
Porcelain is thin and dense, so it is laid on a full mortar bed with a slurry primer on the back.
Before you dig
Patio checks. Tick each item.
Tick each item as you go.
Hire a plate compactor for the sub-base and compact it in layers of no more than 75 mm.
What you get
Patio materials. Each tile explains one result.
With waste.
Tonnes.
Tonnes.
Depth.
Square metres.
Order stone and sand in bulk bags. Each bag holds roughly 0.8 to 1 tonne.
Frequently Asked Questions
No question matches that search.
How many slabs do I need for my patio?
Divide the patio area by the area of one slab plus its joint, then add about five per cent for cuts and breakages.
How deep should a patio base be?
About one hundred millimetres of compacted sub-base for foot traffic on firm ground, and one hundred and fifty on soft soil.
How much sand do I need for a patio?
Multiply the area by the bedding depth in metres and by about one point six tonnes per cubic metre.
How deep do I dig for a patio?
The slab thickness plus the bedding and the sub-base, usually about one hundred and fifty to two hundred millimetres.
What fall should a patio have?
About one in sixty, away from the house.
How much waste should I allow?
Five per cent for simple layouts and ten per cent or more for curves and patterns.
Can I lay a patio on soil?
No. Without a compacted sub-base the slabs will sink and rock.
Build it once, build it right
Order the right number of slabs and enough stone and sand for a solid base. A good base keeps the patio flat for years.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.