Sand calculator
Loose sand weighs about 1.6 tonnes per cubic metre, so one tonne covers roughly 10 square metres at 60 mm deep. Multiply area by depth for volume, then by the density. Sand compacts as it is screeded, so order about 10% over the raw figure.
How to work out sand
Three sands do three different jobs and are not interchangeable. Sharp sand is coarse and angular, used for laying slabs, screeding and mixing concrete. Building sand: also called soft sand — is fine and rounded, used for mortar where workability matters more than strength. Kiln-dried sand is sharp sand dried and graded for brushing into block-paving joints, and it is the only one that will actually run into a 3 mm gap. Buying the wrong one is the most common mistake on this list, and it does not become obvious until the mortar will not hold or the paving beds unevenly.
Questions
About 10 square metres at 60 mm deep, or 20 square metres at 30 mm. A bulk bag is roughly 0.5 cubic metres.
Sharp sand, either dry-laid at 40–50 mm or in a semi-dry mortar bed. Building sand is too fine and will not hold a level.
200–300 mm gives enough depth to dig. Use washed play sand rather than builders sand, which stains skin and clothes.
Weight, almost always: tonnes or bulk bags. Small bags are quoted in litres or kilograms, which is why this page converts between all of them.
Yes. Expect to lose 5–10% of the loose depth to compaction, more if it is vibrated with a plate compactor.