Work out the volume of any space in m³, then convert it to litres or tonnes of concrete, soil, sand, gravel or mulch.
Slabs, garden beds, trenches, rooms — anything box-shaped.
Approximate densities only — moisture and compaction change real-world weights. Concrete is weighed as placed, not as broken rubble.
A cubic metre (m³) is the volume of a 1 m × 1 m × 1 m cube. Measure everything in metres, then use the formula for your shape.
Length × width × depth. Works for trenches, garden beds, skips and rooms.
3m × 2m × 0.5m = 3 m³
π × radius² × height. Radius is half the diameter — for tanks, columns and round holes.
π × 0.5² × 1.2m = 0.94 m³
Length × width × max height, divided by two — a box cut in half diagonally.
3m × 2m × 0.6m ÷ 2 = 1.8 m³
Working out a concrete pour? Use the concrete calculator — it handles wastage, bags and cost too.
Multiply length × width × height (or depth), all in metres. A trench 3 m long, 2 m wide and 0.5 m deep is 3 × 2 × 0.5 = 3 m³. For round shapes, use π × radius² × height. If you measure in centimetres or millimetres, convert to metres first.
There are exactly 1,000 litres in one cubic metre. So 0.25 m³ is 250 litres, and a 3,000-litre tank holds 3 m³.
It depends entirely on the material. As a rough guide per cubic metre: wet concrete is about 2.4 tonnes (loose broken concrete is closer to 1.2–1.5 t), road base 1.8 t, sand 1.5 t, gravel 1.5 t, topsoil 1.3 t and mulch only around 0.4 t. Moisture and compaction change these figures, so treat them as estimates.
A standard 6×4 box trailer holds about 0.6–0.7 m³ level. Watch the weight, not just the volume — 0.7 m³ of sand weighs over a tonne, roughly double what a typical unbraked 750 kg-rated trailer can legally carry, which is why suppliers recommend around half a cube of sand or soil per trip.
Multiply the area (m²) by the depth or thickness in metres. A 20 m² slab at 100 mm thick is 20 × 0.1 = 2 m³. You can't convert without a depth — square metres measure area, cubic metres measure volume.
ConConnect is the app for concreters, pump operators and subbies — find work, book pumps and crews, and get paid. Join the waitlist and get three months of Plus free at launch.