Soil and Mulch Calculator
Enter the size of your bed and the depth you want to fill. The calculator gives the volume of soil, compost or mulch to buy, in bulk or in bags.
How deep should it be?
| Job | Recommended depth |
|---|---|
| Mulch on beds and around shrubs | 2 to 3 in (5–8 cm) |
| Compost worked into an existing bed | 2 to 3 in (5–8 cm) |
| Compost layer for a new no-dig bed | 4 to 6 in (10–15 cm) |
| Topsoil for a new lawn | 4 to 6 in (10–15 cm) |
| Raised bed for salads and herbs | 6 to 8 in (15–20 cm) |
| Raised bed for tomatoes and root crops | 12 in (30 cm) or more |
How the calculation works
Volume is the area of the bed multiplied by the depth. For a rectangle, multiply length by width. For a circle, multiply 3.1416 by the radius squared. With measurements in feet and a depth in inches, divide the depth by 12 first. One cubic yard equals 27 cubic feet, and one cubic foot equals about 28.3 liters.
Soil and mulch settle after spreading. Buy about 10 percent more than the calculated volume. Bulk delivery by the cubic yard usually costs less than bags for anything over one cubic yard.
Starting from scratch? Read how to start a new garden bed.