Getting the soil quantity right saves money and a second delivery. This calculator converts your garden bed measurements into cubic metres and tonnes for topsoil, compost, garden mix or mulch.
How to use
- Measure your bed in metres and enter the length, width and depth (vegie beds 250–300mm = 0.25–0.3m deep).
- Choose your material — topsoil, compost, garden mix or mulch — each with its own bulk density.
- Keep the 10% extra ticked for settling and wastage, then press Calculate.
Topsoil Calculator
How much soil do you need? Enter your garden bed measurements below — results in cubic metres & tonnes.
Please enter valid numbers for length, width and depth.
Volume needed
Weight
20kg bags (approx.)
Estimates use typical bulk densities shown above. Actual density varies by supplier and moisture — confirm with your landscape supplier before ordering. How our calculators work
Related calculators: Sand Calculator, Mulch Calculator
Frequently asked questions
How much topsoil do I need for a raised garden bed?
A 2.4m × 1.2m bed at 300mm deep is about 0.86m³ — roughly 1.0 tonne of topsoil.
What is the difference between topsoil, garden mix and compost?
Topsoil is screened base soil for filling; garden mix is a ready-to-plant blend; compost is organic matter for improving existing soil.
How deep should soil be in a garden bed?
200–300mm for most plantings, and 300mm for vegie beds.