Why sand should be shown as both volume and weight
Sand fills a space, so volume is the geometric quantity. Suppliers may sell by weight, so an estimated density converts that volume into tonnes or tons. Showing both avoids pretending there is one universal weight for a cubic metre of sand.
Worked example
A 5 m × 3 m paving bed at 5 cm deep has a theoretical volume of 0.75 m³. With 10% extra, the planning volume is about 0.83 m³. At 1.60 t/m³, that is roughly 1.32 tonnes.
Use the density from your supplier
The preset values are estimates, not specifications for every sand product. Choose “Use supplier density” and enter the bulk density quoted for the material being delivered. For the worked example’s 0.825 m³ planning volume, a supplier density of 1.75 t/m³ gives about 1.44 tonnes instead of 1.32 tonnes at the dry-sand preset. Imperial mode accepts lb/yd³ and converts it internally. This affects the weight and bag comparison, but the space to fill remains 0.825 m³.
Moisture changes density
| Condition | What changes | Planning response |
|---|---|---|
| Dry loose sand | Lower bulk weight | Use a dry density estimate. |
| Damp sand | Water adds mass | Use supplier density if ordering by weight. |
| Compacted bedding | Void space reduces | Use finished compacted depth. |
| Different grading | Particles pack differently | Do not assume all sands weigh the same. |
Bulk versus bagged sand
Small jobs may be easier with bags; larger jobs usually make more sense as bulk delivery. The planning options let you enter a bag weight and a supplier order increment so the same project can be viewed both ways.
Irregular areas and changing depth
Split L-shaped beds and paths into simpler rectangles and add the volumes. Where the base is uneven, use several depth measurements rather than one optimistic value. Low spots can consume more sand than the plan area suggests.
Before ordering
- Use the finished depth required by the project.
- Choose the correct sand type for the application.
- Use supplier density for weight-sensitive orders.
- Compare bulk delivery minimums with bagged alternatives.
- Keep base aggregate and jointing sand as separate quantities when they serve different layers.
Keep sand layers separate
A paver project may use bedding sand beneath the pavers and a different jointing product between them. Enter the bedding layer's area and finished depth here. Joint sand depends on joint width, paver geometry and manufacturer coverage, so it should be calculated separately from the bedding volume. A structural aggregate base belongs in the gravel calculator.
Frequently asked questions
Does wet sand take up more volume?
Moisture changes its bulk density and handling. This calculator estimates the measured volume, then uses the selected density to approximate weight; use the supplier's figure for a specific product.
What if the layer is uneven?
Take several depth readings and calculate sections separately. A single minimum depth can underestimate the fill needed for low spots.
Are the bag figures based on volume or weight?
The purchase panel divides the estimated mass by the bag weight you enter. Its result changes with the density assumption; a supplier's stated bag coverage is preferable when available.