Sand Calculator
Work out how much sand you need for paving, mortar, concreting or levelling – in cubic metres, tonnes and 20 kg bags, with the cost in AUD.
Formulas shown on this page · Last reviewed October 2026
How the sand calculator works
volume (m³) = area (m²) × depth (mm) ÷ 1,000
tonnes = volume × (1 + waste) × density (t/m³)
bags = tonnes × 1,000 ÷ bag size (kg)
Sand density is approximate: about 1.5 t/m³ for soft sand and 1.6–1.7 t/m³ for sharp or bedding sand, and damp sand is heavier than dry. Edit the density above if your supplier gives a figure.
Types of sand and where they are used
| Type | Approx. density | Typical depth |
|---|---|---|
| Bricklayers’ / soft sand | 1.5 t/m³ | Mixed into mortar |
| Concreting / sharp sand | 1.6 t/m³ | Mixed into concrete or screed |
| Paving / bedding sand | 1.6 t/m³ | 25–50 mm bedding layer |
Soft bricklayers’ sand suits mortar and rendering; concreting sand suits concrete and screeds; paving sand is for bedding pavers.
Buying sand in Australia
Bagged sand (commonly 20 kg) is sold at hardware stores, while landscape supplies yards sell it by the cubic metre or tonne for larger jobs. In hot, dry weather, keep stockpiled sand covered and dampen the bedding layer lightly so it screeds evenly.
At the default prices, a 20 kg bag costs $7.00, which works out to about $350 per tonne in bags, compared with roughly $75 per tonne loose. Bulk is far cheaper per tonne once you need more than around half a tonne. These are typical prices – check your local supplier.
Frequently asked questions
How much sand do I need for a 4 × 3 m area at 50 mm deep?
The base volume is 0.6 m³. With 10% extra that is 0.66 m³, or about 0.99 tonnes at 1.5 t/m³.
How many 20 kg bags is that?
0.99 tonnes is 990 kg, which needs 50 bags of 20 kg (rounded up) – about $350 at the default price.
How many tonnes of sand are in a cubic metre?
Around 1.5–1.7 tonnes, depending on the type and moisture. One cubic metre of bricklayers’ / soft sand is about 1.5 tonnes.
What sand should I use under paving?
Use a coarse, sharp or dedicated bedding sand, levelled to about 25–50 mm and compacted. Soft mortar sand is too fine and can wash out.