How to calculate topsoil
Topsoil is sold in bags by the cubic foot and in bulk by the cubic yard. Find the area you're covering, multiply it by the depth, convert to cubic yards, and add some extra because loose soil settles.
Cubic yards = length (ft) × width (ft) × depth (in) ÷ 12 ÷ 27
Tons ≈ cubic yards × 1 (dry topsoil)
Example: a 30 × 20 ft lawn area covered 4 inches deep needs 30 × 20 × 4 ÷ 12 = 200 cubic feet, or 7.4 cubic yards. With 10% extra for settling, order about 8.2 cubic yards.
How deep should topsoil be?
| Project | Typical depth |
|---|---|
| Top-dressing an existing lawn | 1/4–1/2 in |
| Leveling low spots | 1–2 in at a time |
| New lawn (seed or sod) | 4–6 in |
| Flower beds | 6–8 in |
| Vegetable garden | 8–12 in |
| Raised beds | full bed depth, often 10–12 in |
Bulk or bags?
Bags are handy for a raised bed or a few patches, and you can carry them into a backyard without a wheelbarrow brigade. For anything over about 2 cubic yards, bulk is usually far cheaper, even after a delivery fee. Enter both prices above to compare.
Tips for spreading topsoil
- Loosen the ground underneath first, so the new soil blends in and roots can grow down.
- Have bulk soil dumped on a tarp close to where you need it. It's much easier to clean up.
- Water lightly after spreading and check for low spots once it settles before seeding or laying sod.
Frequently asked questions
How deep should topsoil be for a new lawn?
Most new lawns, whether seeded or sodded, do well on 4 to 6 inches of good topsoil over loosened subsoil. Top-dressing an existing lawn uses only about 1/4 to 1/2 inch, spread thin enough that grass pokes through.
How much does a cubic yard of topsoil weigh?
Dry topsoil weighs roughly 2,000 lb, or about 1 ton, per cubic yard. Wet soil can weigh considerably more, which matters if you're hauling it in a pickup truck.
How many bags of topsoil are in a yard?
A cubic yard is 27 cubic feet, so it equals 27 bags of 1 cubic foot or 36 bags of 0.75 cubic foot. For more than a couple of yards, bulk delivery is almost always cheaper.
How much soil do I need for a raised bed?
Multiply the bed's length by its width and its depth. A 4 × 8 ft bed filled 12 inches deep needs 32 cubic feet, about 1.2 cubic yards. Raised beds are usually filled with a garden soil or topsoil and compost blend rather than plain topsoil.
Should I order extra topsoil?
Yes, about 10 to 15 percent. Loose topsoil settles after it's spread and watered, and low spots usually take more than you measured.