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Topsoil Calculator
Calculate how much topsoil you need for a new lawn, a garden bed or a raised bed. You get cubic yards for bulk delivery, an approximate weight, and the number of bags if you are buying from a garden centre.
Results are estimates. Soil, stone and mulch settle, weigh differently and vary by supplier. Confirm quantities and local requirements before ordering.
How to calculate it
Topsoil is bought by volume, so multiply area by depth. Length × width gives square feet, and multiplying by the depth in feet (4 inches = 0.333 ft) gives cubic feet. Divide by 27 for cubic yards.
Formula: cubic yards = length (ft) × width (ft) × depth (in) ÷ 12 ÷ 27.
One cubic yard covers about 324 square feet at 1 inch, 162 at 2 inches, 108 at 3 inches and 81 at 4 inches. Loose topsoil is usually 1.0–1.4 tons per cubic yard, and wet soil is heavier.
Worked example
A 25 ft × 20 ft lawn area with 4 inches of topsoil and 10% extra:
| Area | 500 sq ft |
|---|---|
| Volume (no extra) | 166.7 cu ft 6.17 cubic yards |
| Bulk topsoil to order | 6.79 cubic yards includes 10% extra |
| Approx. weight | 6.8–9.5 tons loose topsoil is roughly 1.0–1.4 tons per cubic yard; wet soil is heavier |
| 0.75 cu ft bags (about 40 lb) | 245 bags |
| 1 cu ft bags | 184 bags |
| Cubic meters | 5.19 m³ |
Common topsoil depths
| Use | Typical depth |
|---|---|
| Overseeding an existing lawn | ½–1 inch |
| Levelling low spots | 1–2 inches |
| New lawn | 4–6 inches |
| Garden beds | 6–8 inches |
| Raised beds | 8–12 inches |
Tips
- Loosen the soil underneath before spreading new topsoil so the layers bond instead of sitting apart.
- Order a bit extra. Soil compacts after watering and rain, and settles after a few weeks.
- Bulk topsoil is usually far cheaper per cubic foot than bagged, but check delivery fees and minimum loads.
- Ask the supplier for screened topsoil if you are planting. Unscreened loads can contain stones and debris.
Frequently asked questions
How much topsoil do I need for a lawn?
A new lawn typically needs 4–6 inches. A 25 ft × 20 ft lawn at 4 inches needs about 6.2 cubic yards before any extra allowance.
How many bags of topsoil make a cubic yard?
A cubic yard is 27 cubic feet. That is 36 bags of 0.75 cubic foot topsoil or 27 bags of 1 cubic foot topsoil.
How much does a cubic yard of topsoil weigh?
Roughly 1.0–1.4 tons when loose, and more when wet. If you are hauling it yourself, check the load limit for your truck or trailer.
Is topsoil the same as garden soil?
No. Topsoil is the natural upper layer of soil, and it is usually cheaper. Garden soil and raised-bed mixes have compost or other amendments added. Calculate volume the same way for either.