The formula
Cubic feet = area (sq ft) × depth (in) ÷ 12 Cubic yards = cubic feet ÷ 27 Bags = cubic feet ÷ bag size Tons = cubic yards × 1.1
Example: a 10 × 20 ft area at 4 inches deep needs 66.7 cubic feet, which is 2.47 cubic yards, 89 bags of 0.75 cubic feet, or about 2.7 tons.
Quick answers for common areas
| Area | 4 in deep | 6 in deep |
|---|---|---|
| 100 sq ft | 1.23 yd³ · 45 bags | 1.85 yd³ · 67 bags |
| 200 sq ft | 2.47 yd³ · 89 bags | 3.7 yd³ · 134 bags |
| 500 sq ft | 6.17 yd³ · 223 bags | 9.26 yd³ · 334 bags |
| 1,000 sq ft | 12.35 yd³ · 445 bags | 18.52 yd³ · 667 bags |
How deep to spread topsoil
- 4 to 6 inches under a new lawn, whether you seed or lay sod.
- 6 to 12 inches for vegetable and flower beds; raised beds are filled to their full height.
- 1/4 to 1/2 inch when top-dressing an existing lawn.
Once you need more than a yard or two, bulk delivery is usually far cheaper than bags. Add both prices above to compare.
Sources and assumptions
The weight uses 1.1 tons per cubic yard (about 2,200 lb), a typical figure for dry screened topsoil; wet soil is heavier. The 0.75 cubic foot bag is the common 40 lb retail bag.
Questions
How many bags of topsoil are in a yard?
36 bags of 0.75 cubic feet, 27 bags of 1 cubic foot, or 18 bags of 1.5 cubic feet.
How much does a yard of topsoil weigh?
About 2,000 to 2,200 lb dry, roughly 1.1 tons. Wet topsoil can weigh much more.
How much area does a yard of topsoil cover?
About 81 square feet at 4 inches deep, or 54 square feet at 6 inches.