How to Calculate Topsoil
Topsoil is the top 2 to 12 inches of soil where nearly all plant roots live. Whether you are installing a new lawn, building raised beds, leveling a yard, or prepping a garden, ordering the right volume prevents wasted money and a half-finished project. This calculator converts your length, width, and depth into cubic yards, cubic meters, tons, and bag counts - the four numbers suppliers actually use when quoting prices.
Rectangular Area Formula
Most lawn and bed projects are rectangular. Multiply length by width to get area, then by depth to get volume. Since depth is typically measured in inches (or centimeters) but length and width are in feet (or meters), the units need conversion:
There are 27 cubic feet in one cubic yard, and 12 inches in one foot. For metric, multiply length (m) by width (m) by depth (m, which is cm divided by 100) to get cubic meters directly.
Circular Area Formula
For round tree rings, fire pits, and circular beds, use the area-of-a-circle formula before multiplying by depth:
Converting Volume to Weight
Suppliers often price topsoil by the cubic yard but charge delivery based on weight and distance. Knowing the tonnage helps you compare quotes and plan truck logistics. Density depends on moisture and type:
Raised bed fill: 8 to 12 inches for most vegetables; 18 to 24 inches for root crops.
Top-dressing established lawn: 1/4 to 1/2 inch after core aeration.
Regrading / slope correction: layer in 2-inch lifts with compaction between each layer.
Topsoil Types Compared
Not all topsoil is created equal. Screened and amended blends cost 30 to 50 percent more but save hours of hand-picking rocks and adding compost after delivery:
| Type | Density (lb/cu ft) | Best Use | Typical Price |
|---|---|---|---|
| Standard | 76 | Grading, fill, rough work | $15-25 / cu yd |
| Screened | 72 | Lawn prep, under sod | $25-35 / cu yd |
| Premium Blend | 70 | Ornamentals, shrub beds | $35-50 / cu yd |
| Garden Mix | 66 | Vegetable beds, raised beds | $40-60 / cu yd |
| Sandy Loam | 82 | Drainage areas, slopes | $30-45 / cu yd |
Standard Bag Sizes
Bagged topsoil is convenient for small jobs but costs 2 to 4 times more than bulk per cubic yard. Here is how many bags equal one cubic yard:
Settling and Over-Order Factor
Fresh topsoil settles 10 to 20 percent over the first year as air pockets collapse and organic matter decomposes. Order 10 percent extra to account for settling plus minor spillage during installation. For deep fills (over 8 inches), compact each 2-inch lift with a plate compactor or hand tamper to minimize future settling.
After-Installation Timeline
- Day 1-7: water lightly to settle the topsoil. Wait before seeding.
- Day 7-14: rake smooth, remove any surface debris, then seed or sod.
- Year 1: expect 10-20% settling. Top-dress low spots in fall.
- Year 2+: lawn roots stabilize. Top-dress 1/4 inch annually after aeration.