Topsoil Calculator
Calculate how much topsoil you need for a new lawn or garden bed, including an allowance for settling – in cubic metres, tonnes and 25 L bags.
Formulas shown on this page · Last reviewed October 2026
How the topsoil calculator works
volume (m³) = area (m²) × depth (mm) ÷ 1,000
order (m³) = volume × (1 + settling allowance)
tonnes = order (m³) × density (kg/m³) ÷ 1,000
Loose topsoil weighs roughly 1,200–1,400 kg/m³ (about 1,300 kg/m³ is used by default). Freshly spread soil settles by around 15–20% as it is watered and compacted, so the calculator adds 15% to the volume you enter.
How deep should topsoil be?
| Project | Depth |
|---|---|
| Levelling or patching an existing lawn | 25–50 mm |
| New lawn from seed or turf | 100 mm |
| Flower and shrub beds | 150–300 mm |
| Vegetable beds and raised beds | 200–300 mm |
Buying topsoil in Canada
Common products include screened topsoil, garden soil mix and triple mix. Home centres sell bagged soil in roughly 25 L bags, while landscape yards deliver by the cubic yard or tonne, so cubic yards are shown as well. After a long winter, wait until the ground has thawed and dried out before spreading. Spring and early autumn are the usual windows for new lawns.
At the default prices, a 25 L bag is $6.00, or about $240 per cubic metre, while bulk soil is roughly $45 per m³ before delivery. Bulk is usually cheaper once you need more than about half a cubic metre. These are typical prices – check your local supplier.
Frequently asked questions
How much topsoil do I need for a 10 × 5 m lawn at 100 mm?
The base volume is 5 m³. With a 15% settling allowance you should order 5.75 m³, which weighs about 7.5 tonnes at 1,300 kg/m³.
How many 25 L bags is that?
5.75 m³ is 5,750 litres, so you need 230 bags of 25 L (rounded up) – about $1,380 at the default price.
How many cubic yards of topsoil is that?
One cubic yard is 0.765 m³, so 5.75 m³ is about 7.52 yd³.
Why add an allowance for settling?
Loose soil compacts as it is raked, watered and walked on. Without an allowance your finished level can end up 15–20% lower than planned.