How much topsoil do you need?

Your topsoil order starts with three measurements: the length, width, and depth of the space you want to fill. Bag count and delivery size come after that.

Measure the space you will actually fill

For a rectangular bed, multiply length by width. A bed measuring 12 feet by 8 feet has an area of 96 square feet. If part of that area is occupied by a path or a permanent feature, subtract that part before working out the volume.

For an irregular bed, sketch it as a few rectangles or circles. Measure and calculate each section, then add the results. Do not include an overlap in two sections. For a circle, area is π × radius²; the radius is half the diameter.

Choose a depth for your project

The calculator cannot decide which depth is appropriate for your plants or existing ground. Measure the space available and consider what the material is intended to do. A shallow surface layer and a bed that needs filling are different jobs.

Check depth in several places if the ground is uneven. An average depth is more useful than taking the shallowest point. Avoid treating the calculator’s prefilled four-inch example as a planting recommendation.

A worked example

A 12 × 8 ft bed with a planned 4-inch layer needs 32 cubic feet, or about 1.19 cubic yards, before any allowance. If you choose 10% extra, the working estimate becomes about 35.2 cubic feet, or 1.30 cubic yards.

Allowances are estimates, not a compaction model

Compaction changes soil pore space and bulk density. The amount of settling in your project depends on the material and how it is handled. An extra percentage is a practical planning choice; it does not predict exactly how much the soil will settle.

Ask the supplier about the product you are buying and whether their advice refers to loose or placed material. Adjust the allowance rather than adding the same margin repeatedly to area, depth, and final volume.

Turn the estimate into a purchase

For bags, use the volume printed on the package. Weight alone is not enough to infer volume reliably. The calculator rounds the total up to complete bags.

For bulk orders, check delivery increments and minimum quantities. A displayed estimate of 1.30 cubic yards does not mean a supplier will deliver exactly 1.30 yards. Confirm where the load can be placed and include delivery when comparing costs.

Calculate your topsoil →