Sand calculator
Sand is sold either by volume or by weight, so it helps to know both. The calculator gives the volume of the layer and its approximate weight, so you can compare quotes and choose the right delivery.
Your measurements
Result
- Sand volume
- 0.75 m³
- Estimated weight
- 1.20 t
The layer settles when compacted — order 10–30% more than the finished thickness, depending on the material.
How the calculation works
- Volume (m³) = length × width × layer thickness.
- Weight (tonnes) = volume × 1.6 t/m³, the average density of loose sand.
Worked example
A 5 cm layer under a 5 × 3 m path is 5 × 3 × 0.05 = 0.75 m³ of sand — about 1.2 tonnes.
What the calculator assumes
- 1.6 t/m³ is for loose, slightly damp sand; wet sand reaches 1.8–1.9 t/m³.
- Suppliers sell by the cubic metre or by the tonne — the weight helps you compare offers and pick the truck.
When to adjust the result
- The layer settles when compacted: for a finished thickness of 5 cm, order 10–15% more.
- Paving is bedded on washed sand or fine grit (0–4 mm), not sand containing soil.
Using the right sand
Sand is not interchangeable. Washed sharp sand (coarse, angular) is for concrete, screeds and paving beds; soft building sand (finer, rounded) is for mortar and render where workability matters; fine kiln-dried sand is for brushing into paving joints.
Sand bulks when damp — a damp heap can occupy up to about 25% more volume than the same sand dry — so batching by volume with wet sand gives weaker mixes. Store sand on a hard surface, covered, so it stays clean and does not wash away.
Frequently asked questions
How much does a cubic metre of sand weigh?
About 1.6 tonnes when loose and slightly damp, up to around 1.9 tonnes when wet.
How thick should the sand bed under paving be?
Commonly 3–5 cm of bedding sand or grit over a compacted sub-base; follow the paving manufacturer's system.
How much sand is in a bulk bag?
Typically around 0.6–0.8 m³ or close to a tonne, depending on the supplier; check the stated weight or volume.
Can I use builder's sand for concrete?
Concrete needs sharp sand plus gravel; soft building sand makes concrete weaker and more prone to cracking.