Sand calculator
The calculator needs JavaScript. The worked example, formula and figures below show exactly how it works, so you can do the sum yourself. A guide, not advice. Check your supplier's or maker's figures before ordering.
Short answer
Work out how much sharp sand, building sand or ballast to order. Enter your measurements below; every figure we start from is shown and you can change it.
Worked example
| You enter | Value |
|---|---|
| Area | rectangle 3 m × 3 m |
| Depth | 50 mm |
| Material | Sharp sand |
| Density | 1.6 t/m³ |
| Waste allowance | 0% |
| Bulk bag size | 0.85 t |
| Small bag size | 25 kg |
Order: 1 bulk bag
| Result | Value |
|---|---|
| Bulk bags | 1 |
| Small bags | 29 |
| Weight | 720 kg |
| Volume (with waste) | 0.45 m³ |
| Area | 9 m² |
Show the working
- Area: Area 1 9 m² = 9 m²
- Volume: 9 m² × 0.05 m = 0.45 m³
- With 0% waste: 0.45 × 1 = 0.45 m³
- Weight: 0.45 m³ × 1.6 t/m³ = 0.72 t
- Bulk bags: 0.72 t ÷ 0.85 t = 0.85, rounded up to 1
- Small bags: 720 kg ÷ 25 kg = 28.8, rounded up to 29
How it works
- Volume (m³) = area (m²) × depth (m) × (1 + waste)
- Weight (t) = volume (m³) × density (t/m³)
- Bulk bags = weight (t) ÷ bulk bag size (t), rounded up
- Small bags = weight (t) × 1,000 ÷ small bag size (kg), rounded up
Damp sand bulks up, so order by weight, not volume.
Our default (adjustable)
These are typical planning figures and our own allowances, not facts about your product. Change any of them in the calculator to match your bag, pack or tin.
| Figure | Our default (adjustable) | Kind | Source |
|---|---|---|---|
| Density: Sharp sand | 1.6 t/m3 Sources range 1.6–1.7 t/m3 | Typical value Not yet checked against the source | aggregatecalculator.co.uk aggregate density table (checked 19 October 2026) Damp sand bulks; order by weight. |
| Density: Building sand | 1.5 t/m3 Sources range 1.4–1.6 t/m3 | Typical value Not yet checked against the source | aggregatecalculator.co.uk aggregate density table (checked 19 October 2026) |
| Density: Ballast | 1.8 t/m3 Sources range 1.7–1.9 t/m3 | Typical value Not yet checked against the source | aggregatecalculator.co.uk aggregate density table (checked 19 October 2026) |
| Waste allowance | 5 % | Our assumption Not yet checked against the source | Our choice: change it to suit your job Spreading and settling; compaction varies. |
| Bulk bag size | 0.85 t | Common UK size Not yet checked against the source | builder.tools bulk bag figure (checked 19 October 2026) Varies by merchant; check yours. |
| Small bag size | 25 kg | Common UK size Not yet checked against the source | From your product Common small bag. |
FAQs
Guides
Sharp sand vs building sand
The difference between sharp sand and building sand, which job each is for, why damp sand bulks and how to order.