Home / Calculators / Guides / Topsoil Depth Guide: How Deep Should Topsoil Be?
Updated September 2026 · Free reference guideTopsoil Depth Guide: How Deep Should Topsoil Be?
The right topsoil depth depends on what you are building. Use these ranges as planning guidance, then calculate the volume with the Topsoil Calculator.
Typical topsoil depths
| Project | Typical depth | Planning note |
|---|---|---|
| Existing lawn top-dressing | ¼–½ in | Use a thin, even layer so existing grass remains exposed. |
| New lawn / turf preparation | 4–6 in | Use enough quality soil to establish a workable root zone. |
| Flower and planting beds | 6–12 in | Depth varies with existing soil and the plants being installed. |
| Vegetable / raised beds | 8–12 in+ | Deeper beds may suit crops with larger root systems. |
How depth changes quantity
Multiply length and width in feet by depth in feet, then divide cubic feet by 27.
Cubic feet = length × width × (depth in ÷ 12)
Cubic yards = cubic feet ÷ 27
Cubic yards = cubic feet ÷ 27
Example: 20 ft × 10 ft × 6 in = 100 ft³ = about 3.70 yd³ before any allowance.
Ordering allowance
Loose soil can settle after spreading and watering. A planning allowance of roughly 5–10% can help with settling and uneven areas, but it should not replace site measurements or supplier advice.