Soil & Topsoil Calculator

Estimate the soil or topsoil volume needed for a rectangular area at a uniform depth. Calculate cubic yards, cubic feet, and cubic meters. If buying bagged soil, enter the volume printed on the bag to estimate whole bags.

How much topsoil do you need?

Use the inside dimensions of the space you intend to fill and the depth of the soil layer being added. This is a geometric estimate, not a recommendation for soil type or planting depth.

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How to calculate topsoil needed

Cubic yards = length (feet) x width (feet) x added soil depth (inches) / 324

For a 12-foot by 9-foot area receiving a 3-inch layer, 12 x 9 x 3 / 324 = 1 cubic yard, or 27 cubic feet. This is a measurement example; the appropriate depth depends on the project.

Filling a bed versus adding a topsoil layer

For an empty rectangular bed, measure its internal length and width and the intended fill depth. If the space already contains soil, enter only the depth you plan to add, not the total height of the bed. For example, adding 2 inches to a 4-by-8-foot bed requires 4 x 8 x 2 / 12 = approximately 5.3333 cubic feet, before allowances.

This calculator does not subtract rocks, existing plants, drainage layers, or buried objects. Account for the actual space you plan to fill when measuring.

Soil bags and bulk delivery

One cubic yard equals 27 cubic feet. With bags labeled 2 cubic feet, 27 / 2 = 13.5 bag equivalents, so the whole-bag estimate is 14 bags. With 1-cubic-foot bags, it is 27 bags. A bag's weight is not a reliable substitute for its labeled volume.

Bulk soil may be sold by cubic yard or by weight. This tool gives volume, not a universal tonnage conversion. Ask the supplier how the specific product is measured and delivered.

Metric soil formula

Cubic meters = length (m) x width (m) x added depth (cm) / 100

A 5 m by 2 m area receiving a 10 cm layer has a geometric volume of 1 cubic meter, or 1,000 liters. At 50 liters per bag, that is 20 bags.

Frequently asked questions

Are soil and topsoil the same product?

The same geometric formula can estimate volume, but the calculation does not tell you which product to choose. Topsoil, potting mixes, compost blends, and fill materials have different properties and uses. Check the intended application with your supplier or a suitable gardening professional.

How much does a cubic yard of soil weigh?

There is no single weight for every soil. Composition, moisture, and packing affect bulk density. Ask your supplier for product-specific information and confirm whether weight units mean US short tons or metric tonnes.

Should I add extra for settling?

The tool adds no automatic percentage. Ask the supplier how loose delivered volume relates to your finished layer and whether your project needs an allowance. Whole-bag rounding is separate from any settling allowance.

Can I use a bag labeled in quarts?

Not directly in this version. Obtain a cubic-foot or liter equivalent from the manufacturer. Do not assume that a US dry quart of soil uses the same conversion as a liquid quart.

Can I calculate an irregular area?

Split a suitable area into non-overlapping rectangles and calculate each one. Add the volumes before calculating whole bags to avoid rounding every section separately. Slopes or changing depths require appropriate measurements beyond a single uniform-depth rectangle.

What happens when I change units?

Length, width, and depth clear so feet are not reused as meters. The optional bag size retains its own selected unit. Enter new dimensions before calculating again.

What inputs are supported?

Positive dimensions with up to four decimal places: length and width up to 10,000 and depth up to 1,000 in displayed units. Optional bag volume must be positive and no more than 10,000 cubic feet or liters. Use a decimal point or comma without thousands separators.

Related calculators

For area alone, use the Square Footage Calculator. For a separate layer, use our Mulch Calculator or Gravel Calculator.

HandyMetric provides general estimation aids, not soil testing, horticultural specifications, or installation services. Verify product suitability, measurements, and order quantities before purchasing.