The coverage formula
Coverage is the topsoil calculation run backwards. Instead of area × depth = volume, it is volume ÷ depth = area.
square feet = cubic feet ÷ (depth in inches ÷ 12) square feet = cubic yards × 324 ÷ depth in inches
Example: 3 cubic yards spread 4 inches deep covers 3 × 324 ÷ 4 = 243 square feet, about a 15.6 × 15.6 ft square, or a 24 × 10 ft strip.
Example with tons: a supplier quotes 5 tons. At about 1.2 tons per cubic yard that is 4.17 cubic yards, which covers 4.17 × 324 ÷ 2 = 675 square feet at 2 inches. If the soil is wet and heavy (1.4 tons per yard) the same 5 tons is only 3.57 yards and covers about 579 square feet.
How much a cubic yard of topsoil covers
| Depth | 1 cubic yard | 2 cubic yards | 5 cubic yards | 10 cubic yards |
|---|---|---|---|---|
| ¼ inch | 1,296 sq ft | 2,592 | 6,480 | 12,960 |
| 1 inch | 324 sq ft | 648 | 1,620 | 3,240 |
| 2 inches | 162 sq ft | 324 | 810 | 1,620 |
| 3 inches | 108 sq ft | 216 | 540 | 1,080 |
| 4 inches | 81 sq ft | 162 | 405 | 810 |
| 6 inches | 54 sq ft | 108 | 270 | 540 |
How much a ton of topsoil covers
Topsoil weighs about 1 to 1.4 tons per cubic yard, so a ton is 0.71 to 1 cubic yard. Coverage for one ton:
| Depth | Dry, light soil (1.0 t/yd³) | Middle (1.2 t/yd³) | Wet, heavy soil (1.4 t/yd³) |
|---|---|---|---|
| 1 inch | 324 sq ft | 270 sq ft | 231 sq ft |
| 2 inches | 162 sq ft | 135 sq ft | 116 sq ft |
| 3 inches | 108 sq ft | 90 sq ft | 77 sq ft |
| 4 inches | 81 sq ft | 68 sq ft | 58 sq ft |
| 6 inches | 54 sq ft | 45 sq ft | 39 sq ft |
Why the spread? A lot of the weight of soil is water. If you buy by the ton, ask the supplier what their topsoil weighs per yard. The page on how much a yard of topsoil weighs explains more.
How much a bag of topsoil covers
| Bag size | 1 inch | 2 inches | 3 inches | 4 inches | 6 inches |
|---|---|---|---|---|---|
| 0.75 cu ft | 9 sq ft | 4.5 | 3 | 2.25 | 1.5 |
| 1 cu ft | 12 sq ft | 6 | 4 | 3 | 2 |
| 1.5 cu ft | 18 sq ft | 9 | 6 | 4.5 | 3 |
| 2 cu ft | 24 sq ft | 12 | 8 | 6 | 4 |
Bags look like they go further than they do. A 10 × 10 ft bed at 3 inches needs 25 bags of 1 cubic foot. The bags of soil calculator works out a full order.
Using coverage to compare quotes
Coverage is handy when suppliers quote different units. Turn each quote into square feet at your planned depth, then into a price per square foot:
- Work out the coverage of what each supplier is offering, using the calculator above.
- Divide each total price (including delivery) by its square feet.
- The lower price per square foot is the better deal, provided the soil quality is the same.
More on comparing prices in how much is topsoil.
Coverage figures are for loose topsoil as delivered. Raked, rolled and watered soil settles, so the finished layer is a little thinner than when you spread it.
Questions gardeners ask
- How much does a yard of topsoil cover?
- One cubic yard covers 324 square feet at 1 inch deep, 162 at 2 inches, 108 at 3 inches, 81 at 4 inches and 54 at 6 inches.
- How much area does a ton of topsoil cover?
- At about 1.2 tons per cubic yard, a ton is about 0.83 cubic yards, which covers roughly 270 square feet at 1 inch, 135 at 2 inches and 68 at 4 inches. Wetter, heavier soil covers less per ton.
- How much does a bag of topsoil cover?
- A 1 cubic foot bag covers 12 square feet at 1 inch deep, 6 at 2 inches and 3 at 4 inches. A 0.75 cubic foot bag covers 9 square feet at 1 inch.
- What is the formula for soil coverage?
- Square feet covered = cubic feet ÷ (depth in inches ÷ 12). For cubic yards, square feet = cubic yards × 324 ÷ depth in inches.