Paver Calculator
Enter the patio or path size in metres to get the number of pavers, tonnes of road base / crushed rock, bedding sand and an estimated cost in AUD.
Formulas shown on this page · Last reviewed October 2026
Tonnes assume the thickness you enter is the compacted depth, using about 2.1 t/m³ for the base and 1.6 t/m³ for sand. Suppliers’ densities vary, so confirm with your merchant.
How the paver calculator works
pavers = area ÷ ((width + joint) × (length + joint)) × (1 + waste)
tonnes = area (m²) × depth (mm) ÷ 1,000 × density (t/m³)
Choose a common size for Australia – the presets cover the sizes most often sold as pavers at landscape suppliers and paving yards – or enter a custom size. Joint width is added to each unit, and about 10% extra covers cuts and breakages.
Base and bedding layers
Road base or crushed rock is compacted in layers, commonly about 100 mm for patios and paths; driveways need more. The calculator uses 100 mm of road base / crushed rock and 30 mm of bedding sand by default; both depths are editable.
| Layer | Default depth | Density used |
|---|---|---|
| road base / crushed rock | 100 mm (compacted) | 2.1 t/m³ |
| bedding sand | 30 mm | 1.6 t/m³ |
Depths are treated as the finished, compacted thickness, so the density is that of compacted material. Loose material is lighter per cubic metre but compacts down by around a fifth, so both approaches give a similar tonnage to order. An extra 10% allows for uneven ground and spillage.
Clay and sandy soils behave differently, so on reactive clay or poorly drained ground it is worth adding depth and good drainage falls. Prices are typical – check local prices and enter your merchant’s per-tonne rates; delivery is not included.
Frequently asked questions
How many 400 × 400 mm pavers for a 5 × 4 m area?
The area is 20 m². With 5 mm joints and 10% waste you need 135 pavers.
How much road base / crushed rock do I need for 20 m²?
At 100 mm compacted and 2.1 t/m³ that is 4.2 tonnes, or about 4.6 tonnes with 10% extra.
How much bedding sand is needed?
A 30 mm bed over 20 m² is 0.6 m³, about 1.06 tonnes at 1.6 t/m³ with 10% extra – roughly 53 bags of 20 kg.
What will the project cost?
At the default prices the pavers, base and sand for 20 m² come to about $1,516, excluding edging, delivery, labour and plate-compactor hire.