How much topsoil do I need?
Working out how much topsoil to buy comes down to one thing: the volume of the space you're filling. Measure the area, choose a depth, multiply them together, then convert that volume into the unit your supplier sells by — cubic yards, tons, or bags.
To get the weight in tons, multiply the cubic yards by the soil's density — screened topsoil is about 1.1 tons per cubic yard. The calculator above does all of this the instant you type, in whichever units and shape you pick.
Topsoil, garden soil, fill dirt or compost
They're priced and weighed differently, so pick the right one. Topsoil is the nutrient-rich growing layer for lawns and beds. Garden / raised-bed soil is a lighter, blended mix. Fill dirt is heavy subsoil for raising grade and backfilling — cheap and stable, but nothing grows in it. Compost is light and used to enrich existing soil. A common approach is to bulk-fill with fill dirt and cap it with a few inches of topsoil — size the base with the gravel calculator where drainage matters.
Worked example
A new lawn area 20 ft long and 15 ft wide, topped with 3 inches of topsoil:
20 × 15 × 0.25 ÷ 27 = 2.8 cubic yards, or about 3 tons. Add ~10% for settling and you'd order a little over 3 tons.
How deep should topsoil be?
- 0.5–1 inch — top-dressing or overseeding an existing lawn
- 3–4 inches — laying a new lawn over graded ground
- 6–12 inches — garden beds and raised beds
Tap a depth chip in the calculator to drop in one of these common depths without typing.
Typical soil densities
Weight depends on the material and how damp it is. These are the typical dry figures the calculator uses; your supplier's number may differ with moisture and screening — pick Custom density to enter your own.
| Material | Tons / yd³ |
|---|---|
| Topsoil (screened) | 1.1 |
| Garden / raised-bed soil | 1.0 |
| Fill dirt | 1.25 |
| Compost | 0.5 |
Buying bagged soil instead? Switch Sold by to Bag and set your bag size — a 40 lb bag of topsoil is roughly 0.75 ft³. The calculator rounds up to whole bags.
Common questions
How much topsoil do I need?
Multiply your area by the depth to get a volume, then convert to cubic yards or tons. For a rectangle, area is length × width; for a circle it's π × radius². Multiply by depth in feet, divide by 27 for cubic yards, then multiply by the soil density for tons. The calculator above does all of this instantly as you type.
How much does a 40 lb bag of topsoil cover?
A 40 lb bag of topsoil holds roughly 0.75 cubic feet, so it covers about 9 square feet at 1 inch deep, or about 3 square feet at 3 inches deep. Switch Sold by to Bag and set your bag size — the calculator rounds up to the number of whole bags you need.
How much will 1 ton of topsoil cover?
One ton of topsoil is roughly 0.9 cubic yards (topsoil weighs about 1.1 tons per cubic yard). That covers around 240 sq ft at 1 inch deep, about 80 sq ft at 3 inches, or about 60 sq ft at 4 inches. Damp or clay-heavy soil weighs more, so coverage per ton drops a little.
How deep should topsoil be?
For overseeding or top-dressing a lawn, 0.5–1 inch is enough. For a new lawn, aim for 3–4 inches over the graded base. For garden and raised beds, 6–12 inches gives roots room. Tap a depth chip in the calculator to use one of these.
What is the difference between topsoil and fill dirt?
Topsoil is the nutrient-rich upper layer that plants grow in; fill dirt is subsoil with no organic matter, used to raise grade or backfill because it's cheaper and settles firmly. Many projects use fill dirt for bulk volume and cap it with a few inches of topsoil. This calculator includes both, plus garden soil and compost — pick the material to apply the right density.
Does this topsoil calculator work in metric?
Yes. Switch to "Metric" to enter your area in metres and depth in centimetres. The result is shown in cubic metres and tonnes, or bags, so you can order in whichever unit your supplier uses.