How to use the topsoil calculator
- Choose the shape. Rectangle, circle, several parts for L-shapes and curves, or type in the area if you already know it.
- Enter the size and depth. Length and width in feet; depth in inches. Feet and inches like 12' 6" work too.
- Read the result in cubic yards, tons and bags. Under Adjust assumptions you can change the weight per yard, extra and bag size.
- Add your supplier's price per ton, yard or bag to see the cost, including delivery.
The topsoil formula
Cubic feet = area (sq ft) × depth (in) ÷ 12
Cubic yards = cubic feet × (1 + extra) ÷ 27
Tons = cubic yards × weight per cubic yard
Bags = cubic feet with extra ÷ bag size, rounded up
Worked example
A 20 × 10 ft garden, 4 inches of topsoil
- 200 sq ft × (4 ÷ 12) = 66.7 cu ft; with 5% = 70 cu ft.
- 70 ÷ 27 = 2.59 cubic yards.
- At about 1.1 tons per yard: 2.85 tons, or 94 bags of 0.75 cu ft.
How far a cubic yard goes
| Depth | One cubic yard covers | 0.75 cu ft bags per 10 sq ft |
|---|---|---|
| 1 in | 324 sq ft | 1.1 |
| 2 in | 162 sq ft | 2.2 |
| 3 in | 108 sq ft | 3.3 |
| 4 in | 81 sq ft | 4.4 |
| 6 in | 54 sq ft | 6.7 |
A cubic yard is 27 cubic feet, or 36 bags of 0.75 cu ft.
Typical topsoil depths
- New lawn from seed or sod: 4 to 6 in.
- Vegetable and flower beds: 6 to 12 in.
- Top-dressing a lawn: 1/4 to 1/2 in.
- Filling low spots: the depth of the dip, plus settling.
Common mistakes to avoid
- Ordering by the ton without checking. Suppliers sell by the yard or ton; confirm which before you compare prices.
- No allowance for settling. Fresh topsoil compacts; add 10 to 20% for leveling jobs.
- Spreading on wet days. Wet soil compacts into clods and is hard to rake level.
- Burying the crowns. Keep fresh soil below the base of existing plants.
Frequently asked questions
How much topsoil do I need for a lawn?
For a new lawn, 4 to 6 inches of topsoil is common. At 4 inches, one cubic yard covers 81 sq ft; at 6 inches, 54 sq ft. Top-dressing an existing lawn needs only 1/4 to 1/2 inch.
How much does a yard of topsoil weigh?
About 1 to 1.3 tons, depending on moisture and how much clay it contains. Wet topsoil can be noticeably heavier. We use 1.1 tons by default.
How many bags of topsoil make a yard?
27 cubic feet make a yard: 36 bags of 0.75 cu ft, 27 bags of 1 cu ft, or 13.5 bags of 2 cu ft.
Will topsoil settle?
Yes. Loose topsoil can settle 10 to 20% as it is watered and walked on. For filling and leveling, add more extra under Adjust assumptions.
Topsoil or garden soil?
Topsoil is screened natural soil for lawns and fill. Garden soil or raised bed mix is topsoil blended with compost for planting, and costs more.