Trade & construction Australia
Sand Calculator Australia
Sand for paving bedding, concrete mixes, play areas and levelling is sold by the tonne or cubic metre, and the right depth depends on the use. This calculator turns the area and depth into cubic metres, then tonnes using a typical density, with an allowance for settling.
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Compacted or finished depth in millimetres.
Typical for loose material; ask your supplier for their figure.
Tonnes to order
—Cubic metres
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Cubic metres with allowance
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20 kg bags equivalent
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Small trailer loads (about 1 m³)
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Estimated cost
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The working
How much sand do I need?
Multiply length by width by depth in metres to get cubic metres, add an allowance, and multiply by the density to get tonnes. A 4 × 3 m area at 30 mm deep is 0.36 m³, which is about 0.6 tonnes of sand at 1.6 t/m³ with a 10% allowance.
Working out the depth
Paver bedding is usually about 20 to 30 mm, a children's sandpit 200 to 300 mm, and a leveling or fill layer as deep as the job requires.
To find the concrete you need for a slab or footing, use the concrete calculator.
Buying in bulk or bags
Bags suit small jobs, but bulk sand by the tonne or cubic metre is far cheaper per tonne once you need more than a few bags. Many suppliers deliver a minimum quantity, and a delivery fee applies, so check whether a trailer collection suits a small job.
Check the delivery access: a tipper truck needs a clear space to unload, and the load goes where it is dropped.
How this is calculated
The rule, step by step, so you can check any figure by hand.
volume = length × width × depth ÷ 1,000 (depth in mm)volume with allowance = volume × (1 + allowance)tonnes = volume with allowance × density (typically about 1.6 t/m³ for loose sand)bags = tonnes × 1,000 ÷ 20
Density is the number that changes the order. Loose sand weighs about 1.6 tonnes per cubic metre, but moisture, grading and compaction all move it. Wet material can weigh 10% to 20% more, which matters when you are buying by weight and the truck has a limit.
The allowance exists because loose material settles once it is spread and compacted, and some is lost at the edges. Ten to fifteen percent is common for a simple area; use more for uneven ground.
A worked example
A 4 × 3 m area spread 30 mm deep.
- Volume4 × 3 × 0.030 = 0.36 m³
- With 10% allowance0.40 m³
- Tonnes at 1.6 t/m³0.63 t
- 20 kg bags32
About 0.6 tonnes, or 0.4 cubic metres.
Bulk delivery is usually cheaper than bags above about half a cubic metre.
Depth and use
The right depth depends on the use. Sand settles when wet or compacted, and bedding sand screeded for paving is compacted by the pavers, so a 10% allowance is typical. Always check the supplier's recommendation for the product you buy, since grades and blends differ.
What it leaves out
Edging, geotextile, base preparation and compaction equipment are not included. If you are building under a driveway or load, the base needs a proper design.
What this calculator does not do
- Flat areas of constant depth
- Density is typical, not a product specification
- Compaction reduces volume by an amount that depends on the material
- Price is your quote
Common questions
How much sand do I need for pavers?
Bedding sand is about 20 to 30 mm deep. A 4 × 3 m area at 30 mm is 0.36 m³ before allowance, about 0.6 tonnes with 10% at 1.6 t/m³.
How deep should a sandpit be?
About 200 to 300 mm, with edging to hold it in.
How many bags in a tonne?
50 bags of 20 kg weigh one tonne.
Where these numbers come from
- Your Home — Australian Government guide to sustainable homes Independent guidance on insulation, materials and design
- National Construction Code (ABCB) The code that sets minimum building requirements in Australia
Method last reviewed 2026-10-28 This calculator uses fixed rules rather than rates that change, and its method is re-checked against the sources above at least once a year. Out of date? Tell us and we will fix it.
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