How Much Topsoil Do I Need?
To estimate how much topsoil you need, you need two basic measurements: the area you want to cover and the depth of soil you want to add. The larger the area or the deeper the layer, the greater the volume of topsoil required.
For a rectangular area, measure the length and width. If you already know the total square footage or square meters, you can enter the total area directly instead.
Why Topsoil Is Calculated by Volume
Unlike flooring, sod, or paint, topsoil isn't estimated from area alone. You also need to account for depth. Covering the same area with 4 inches of soil requires twice as much material as covering it with 2 inches.
The calculator combines your coverage area and chosen depth to determine the required volume. In U.S. measurements, bulk topsoil is commonly expressed in cubic yards or cubic feet. Metric results can be expressed in cubic meters or liters.
Subtracting Areas That Don't Need Topsoil
Not every part of a measured area necessarily needs soil. Patios, sidewalks, driveways, sheds, landscaping features, and other structures can be excluded.
Measure these areas separately and enter their combined area in the excluded-area field. The calculator subtracts them before determining the required soil volume.
Should I Order Extra Topsoil?
The amount of soil you actually use can differ from a mathematical volume estimate. Soil can settle or compact, and spreading and grading may result in some variation.
The calculator lets you add your own extra percentage rather than automatically assuming one. Enter 0% if you want the calculation based strictly on your measurements, or add an allowance if you want additional material for your project.
Bulk Topsoil vs. Bagged Topsoil
For larger projects, topsoil may be purchased in bulk and sold by volume, such as the cubic yard or cubic meter. Smaller projects may be easier to handle with bagged soil.
Bag and package sizes aren't universal. If you're buying packaged topsoil, check the volume printed on the bag and enter that amount into the calculator. It can then estimate the number of whole packages needed for your project.
Measuring Irregular Areas
For an irregularly shaped yard or garden, divide the area into smaller rectangles or other sections that are easier to measure. Calculate each section separately and add the areas together.
You can enter that combined measurement as the total project area. Areas that won't receive topsoil can then be subtracted using the excluded-area option.
Keep Soil Conditions in Mind
A calculated volume is an estimate of the amount of space the soil needs to fill. Actual results can vary because different soils may settle or compact differently depending on their composition, moisture, handling, and site conditions.
For that reason, the calculator doesn't automatically apply a universal settling, compaction, shrinkage, or “fluff” factor. Use the Extra Soil Allowance field if you want additional material included in your estimate.