How this calculator works
The area is multiplied by the depth in feet, then increased by a settling allowance because loose soil compacts once it is watered and walked on. For several areas, list each on its own line (rectangles, circles by diameter, triangles by base and height), and add “@ depth” for an area with a different depth. Enter bag and bulk prices to see which is cheaper.
Cubic feet = Length × Width × Depth(in)/12 × (1 + Settle%/100)
Cubic yards = Cubic feet ÷ 27
Worked example
Using the default values in the calculator above:
| Input | Value |
|---|---|
| Area | One rectangle |
| Length | 30 ft |
| Width | 20 ft |
| Depth | 4 in |
| Settling allowance | 10 % |
| Bag size | 0.75 cu ft |
| Price per bag (optional) | $0 |
| Bulk price (optional) | 0 $/yd³ |
| Bulk delivery fee | $0 |
| Result | Value |
|---|---|
| Topsoil needed | 8.15 cubic yards |
| 0.75 cu ft bags | 294 bags |
| Volume | 220 cubic feet |
Step by step:
- Volume = 30 × 20 × 4/12 × 1.1 = 220 cu ft
- Cubic yards = 8.148; bags = 220 ÷ 0.75 → 294
Topsoil per 1,000 sq ft
10% settling allowance.
| Depth | Topsoil needed |
|---|---|
| 1 in | 3.4 cubic yards |
| 2 in | 6.79 cubic yards |
| 3 in | 10.19 cubic yards |
| 4 in | 13.58 cubic yards |
| 6 in | 20.37 cubic yards |
Common mistakes to avoid
- Burying the base of existing trees under several inches of new soil.
Frequently asked questions
How much topsoil do I need for a new lawn?
Many guides suggest 4–6 in of good soil under new grass. A 600 sq ft area at 4 in needs about 8.1 cubic yards including 10% settling.
How many bags of topsoil are in a cubic yard?
About 36 bags of 0.75 cu ft, or 27 bags of 1 cu ft.