Whether you're leveling a lawn, filling raised garden beds, or repairing bare patches after construction, getting the right amount of topsoil is essential. Too little and the job isn't done. Too much and you're paying to haul the extra away.
The Topsoil Formula
Cubic yards = (Length × Width × Depth in inches) ÷ 324
All measurements in feet and inches. Divide by 324 to convert to cubic yards.
Recommended Topsoil Depth by Application
| Application | Depth Needed |
|---|---|
| New lawn from seed | 4–6 inches |
| Lawn repair / overseeding | 1–2 inches |
| Raised garden bed | 12–18 inches |
| General landscaping fill | 4–6 inches |
| Grading / leveling | 2–4 inches |
How Many Bags Do You Need?
Bagged topsoil typically comes in 40 lb bags that yield about 0.75 cubic feet. One cubic yard = 27 cubic feet = approximately 36 bags. For anything over 3–4 cubic yards, bulk delivery is much more cost-effective.
Pro Tip: For new lawns, use a blend of topsoil and compost (70% topsoil / 30% compost). The compost improves drainage, adds nutrients, and helps grass establish faster.
Calculate Your Topsoil Needs
Enter your area dimensions and required depth to get cubic yards instantly.
Use Topsoil Calculator →What to Look for When Buying Topsoil
- Screened topsoil — Rocks and debris removed. Best for lawns and garden beds.
- Fill dirt — Cheaper but lower quality. Good for grading, not for growing.
- Blended topsoil — Mixed with compost or sand. Best for vegetable gardens.
- Avoid topsoil with a strong chemical or sewage smell — it may contain contaminants.