Loona Construction Calculators
Gravel, crushed stone, sand or soil for a drive, path or base layer: enter the area and the depth you want, and get the volume and the weight to order — in tonnes for metric bulk bags and deliveries, or cubic yards and US tons in imperial.
At 50 mm deep, one square metre needs 0.05 m³ — about 75 kg at the standard density of 1.5 t/m³. So a tonne covers roughly 13 m² at that depth, before any allowance for compaction.
Over a compacted sub-base: 50 mm (2 in) for paths and drives with a decorative finish. On bare ground, plan a 100–150 mm sub-base layer plus 50 mm of gravel on top. Deeper than about 75 mm of loose gravel walks badly.
Loose materials are sold by weight (tonnes, bulk bags) as often as by volume. Suppliers deliver by the tonne, so the weight figure is the one you order — and the one your vehicle or barrow has to move.
Volume = Length × Width × Depth
Weight = Volume × (1 + Waste %) × Density
Typical loose densities: gravel and crushed stone 1.5 t/m³, sand 1.6 t/m³, topsoil 1.3–1.4 t/m³, bark mulch 0.3–0.4 t/m³. One cubic metre equals 1.308 cubic yards; one tonne equals 1.102 US tons.
1.5 t/m³ for gravel and most crushed stone, 1.6 for sand, about 1.35 for topsoil, 1.7 for dense crushed concrete. If your supplier quotes a coverage figure, back-calculate: tonnes ordered ÷ volume placed gives your local density.
Yes — loose gravel and sub-base compact by roughly 10–15% once rolled or driven on. The default 10% extra allowance covers normal compaction; use 15% for sub-base layers.
Yes — switch to Imperial for feet and inches; the result shows cubic yards and US tons alongside cubic metres and tonnes.
Add this calculator to your own website or blog — it is completely free, needs no sign-up, and always shows the latest version. Copy the code below and paste it into your page where you want the calculator to appear. Keeping the small “Powered by Loona Automation” credit line under the embed helps keep this tool free — but you are free to style or remove it; the tool works either way.