Sand Calculator

How the sand calculator works

Sand is spread by volume but usually sold by the tonne. This calculator gives the weight directly:

Sand (kg) = length (m) × width (m) × depth (m) × bulk density (kg/m³)

Divide by 1,000 for tonnes. Every dimension is in metres, so a 30 mm layer is 0.03.

Worked example: bedding sand under a 5 m × 4 m paved area

1. Area: 5 × 4 = 20 m², at a bedding depth of 30 mm = 0.03 m
2. Volume: 20 × 0.03 = 0.6 m³
3. Bulk density of washed paving sand: about 1,600 kg/m³
4. 0.6 × 1,600 = 960 kg, so order about 1 tonne

Typical bulk densities

Damp sand is heavier and also bulks up (takes more space), so ask your supplier which density they sell by.

Common uses and depths

• Paver bedding: 20–30 mm, screeded
• Sandpit: 250–300 mm of washed play sand
• Under a pool liner or water tank base: as the manufacturer specifies, usually 50–100 mm compacted
• Pipe bedding in trenches: as specified for the pipe, often 75–100 mm under and around the pipe

Common mistakes

• Entering depth in millimetres.
• Using the wrong type: brickie's sand for mortar, washed sand for concrete and paving, play sand for sandpits.
• Forgetting to allow extra for compaction and screeding losses, about 10%.

How many tonnes of sand in a cubic metre?

About 1.5–1.7 tonnes for dry sand and up to about 1.8 tonnes when damp.

How much sand do I need for a sandpit?

Length × width × about 0.3 m depth, multiplied by roughly 1,550 kg/m³. A 2 m × 2 m sandpit needs about 1.9 tonnes.

Which sand is best under pavers?

Washed, coarse sand (sometimes called paving or concrete sand) drains and compacts well. Avoid fine brickie's sand as a bedding layer.

Written by Sam Alex, civil engineer. About the author