Topsoil Calculator: How Many Yards of Soil Do You Need?

Enter the length, width and depth of the area you are filling and this calculator returns the volume in cubic yards, cubic meters and cubic feet, an estimated delivered weight, and the equivalent number of bags. Below the calculator you will find depth guidance for lawns, beds and raised beds, worked examples, a conversion table and advice on ordering.

How the cubic yard calculation works

Landscape materials are sold by volume, but almost nobody measures a garden in cubic yards. The calculation converts the two dimensions you can measure with a tape — length and width — plus the depth you want to finish at, into the unit your supplier quotes.

In imperial units, multiply length and width in feet to get the area in square feet, then multiply by the depth expressed in feet. Depth is nearly always specified in inches, so divide the inches by twelve first. That produces cubic feet. Because a cubic yard is three feet on every side, one cubic yard holds 27 cubic feet, so dividing cubic feet by 27 gives cubic yards.

In metric units the arithmetic is simpler because the units nest cleanly. Multiply length and width in meters by the depth in meters — centimeters divided by one hundred — and the answer is already in cubic meters. One cubic meter is about 1.308 cubic yards, which is the figure the calculator uses when it shows both.

Measuring an irregular area

Most real gardens are not rectangles. Three approaches cover nearly every shape you are likely to meet.

• Split it into rectangles. Divide an L-shaped or stepped bed into two or three rectangles, calculate each separately and add the results. This is the most accurate method for beds that follow the edges of a house or driveway.
• Use an average width. For a bed that tapers, measure the width at several points along its length, average those measurements and treat it as a rectangle. Measuring at three or four points is usually enough.
• Treat curves as circles or ovals. A round bed is π × radius², or roughly 3.14 × radius × radius. An oval is 3.14 × half the length × half the width. Enter that area as the length with a width of 1 to reuse the calculator.

Small measurement errors matter less than you might expect. A six-inch error across a 20-foot bed changes the volume by a few percent, which is well inside the allowance you should already be adding for settling.

Recommended topsoil depths

Depth drives the volume more strongly than anything else, so it is worth choosing deliberately rather than guessing. Doubling the depth doubles the amount of soil you pay for.

For deep fills, it is rarely worth using topsoil all the way down. Cheaper fill material handles the bulk of the volume and a final layer of quality topsoil provides the growing medium where roots actually live.

Worked examples

Topsoil, garden soil and compost are not the same thing

Suppliers use these terms loosely, and the difference affects both how much you need and what it will do once it is in the ground.

Topsoil is the upper layer of native soil, usually stripped from a site and resold. Unscreened topsoil may contain stones, roots and clods. Screened topsoil has been passed through a mesh — often ⅜ or ½ inch — which makes it easier to rake level and more consistent to spread. It is the default choice for lawns and general bed-building, and it is the cheapest of the three by volume.

Garden soil or soil blend is topsoil mixed with compost, sand or bark fines in a defined ratio. It drains better and holds nutrients better than plain topsoil, weighs less per cubic yard, and costs more. It suits planting beds and raised beds where you want a ready-to-plant medium.

Compost is decomposed organic matter. It is a soil amendment rather than a soil. Used alone it holds too much water and settles heavily; mixed at roughly 20–30% into topsoil it improves structure considerably. It is the lightest of the three, at somewhere near 0.6 tons per cubic yard.

If you are filling a raised bed, a common approach is to buy topsoil and compost separately and blend them on site, which usually costs less than an equivalent volume of pre-mixed garden soil.

Bagged or bulk?

Bagged soil is sold in cubic feet — commonly 0.75, 1, 1.5 or 2 cubic feet per bag. Bulk soil is sold by the cubic yard, delivered loose by truck, usually with a minimum order and a delivery fee.

For larger projects, bulk delivery may be more economical than buying bags, depending on local material, delivery and bag prices. Bags win on convenience for small jobs, for anyone without somewhere to tip a load, and when the material has to be carried through a house or down a narrow side passage. The crossover point is worth checking rather than assuming: price one cubic yard in bags against one cubic yard delivered, including the delivery charge, and compare.

Two practical points about bulk delivery. First, a cubic yard of soil occupies a pile roughly 3 ft × 3 ft × 3 ft, so check you have somewhere it can sit without blocking a driveway. Second, most suppliers will not deliver a partial yard, so round your order up to the next whole or half yard.

Estimating weight, and why it is only an estimate

Volume is fixed by geometry. Weight is not. The calculator multiplies the cubic yards by a typical bulk density for the material you select, but the real figure depends on conditions no calculator can see.

• Moisture. Soil delivered after a week of rain can weigh noticeably more than the same soil delivered in dry weather. This is the largest single variable.
• Composition. Clay-heavy soil is denser than sandy soil. Soil with a high organic fraction is lighter than either.
• Screening. Screened material has more air between particles when loose, so it weighs less per cubic yard than the same soil unscreened.
• Compaction. A cubic yard measured loose in a truck bed is not a cubic yard once it has been spread and firmed.

Weight matters mainly for two reasons: suppliers in some regions sell by the ton rather than the yard, and vehicle or trailer capacity is limited by weight rather than volume. A half-ton pickup is at its limit with well under a cubic yard of wet topsoil on board.

How much to order, and allowing for settling

The calculated volume is the finished volume — the space the material occupies once it is in place. Loose material does not stay at its loose volume. Once it is spread, raked, watered and walked on, it consolidates.

A practical approach:

• Add 5% for a level, well-defined area such as a raised bed with rigid sides.
• Add 10% for open ground, beds with soft edges, or anywhere the base is uneven.
• Add 15% where the existing surface is rutted, where you are filling over loose material, or where the depth is a target rather than a fixed measurement.

Running out halfway through is more expensive than over-ordering slightly, because a second delivery usually carries a second delivery fee. Modest leftovers are easy to use up on low spots, pots or a compost heap.

Volume conversion table

The last three rows are a useful shortcut on site: one cubic yard covers 324 square feet at one inch deep, 108 square feet at three inches, and 54 square feet at six inches.

All MaterialYardage calculators

Each calculator is paired with a full guide covering depths, worked examples and ordering advice for that material.

• Topsoil CalculatorCubic yards of soil for lawns, beds and raised beds, with depth guidance and weight estimates.
• Mulch CalculatorCubic yards and bag counts for bark, wood chip and pine straw at 2, 3 or 4 inches deep.
• Gravel CalculatorCubic yards and tons of gravel or crushed stone for driveways, walkways and patio bases.

Concrete, sand, fill dirt and rock calculators are in preparation and will be added to this list as each guide is completed.

Frequently asked questions