Topsoil calculator
Work out how much topsoil you need for a lawn, border or raised bed.
Uses only the sizes you enter.
Show the workings
| Step | Sum | Answer |
|---|---|---|
| Volume | 20 m² × 0.15 m deep | 3 m³ |
| In litres | 3 × 1,000 | 3,000 litres |
Where the figures come from
- Litres in a cubic metre: 1,000 litres per m3. Source: Weights and Measures Act 1985, Schedule 1. Checked 13 November 2026.
How much topsoil do I need?
Multiply the length and width, in metres, by the depth of soil, in metres. A bed 4 m by 1 m filled 300 mm (0.3 m) deep needs 4 × 1 × 0.3 = 1.2 cubic metres.
Topsoil settles after it is spread, so some people order a little extra. Use "Extra to allow" for that. The weight of a cubic metre depends on the soil and how wet it is: your supplier can tell you.