Topsoil Calculator
A bed loses about a fifth of its depth in the first season as soil settles and organic matter breaks down. This calculator adds that back, and converts the result into yards, bags and tons.
Topsoil volume calculator
How far one cubic yard goes
| Spread depth | Square feet covered | Bags (2 cu ft) per 100 sq ft |
|---|
Depth by use
| Job | Depth | Note |
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The number that makes a new bed come up short
Topsoil is delivered loose and settles. Fresh loam with high organic content can lose 15 to 20 percent of its depth in the first season as air works out of it and the compost fraction breaks down. Mulch loses nothing in the same way, because it is supposed to stay coarse. That is why the allowance in this calculator is a separate input rather than a fixed 10 percent: the right number depends entirely on what you are spreading.
Skipping it is the most common reason a newly graded bed sits two inches below the sidewalk the following spring.
How the volume is calculated
Cubic feet is length times width times depth in feet, where depth in feet is inches divided by 12. A 20 by 10 bed at 3 inches is 200 square feet times 0.25 feet, which is 50 cubic feet. There are 27 cubic feet in a cubic yard, so that is 1.85 cubic yards. Add 15 percent for settling and you order 2.13 yards.
Weight matters for two reasons. A half-ton pickup cannot legally carry much more than half a yard of wet topsoil, and delivery charges are often quoted by the ton for anything beyond a few yards. Topsoil at 1.10 tons per yard is the usual working figure, but wet loam runs heavier and dry screened loam lighter.
Yards, bags, or a bulk bag
Bulk is cheaper above about one cubic yard. A 2 cubic foot bag holds 1/13.5 of a yard, so this bed would take 25 bags at roughly $5 each — $125 against $67 in bulk, plus the drive. A one-yard bulk bag, delivered on a pallet, lands between the two and is the right answer when a truck cannot get to the bed.
Below one yard, bags usually win because the delivery minimum on bulk soil is often two or three yards. If you need half a yard, ask whether the yard charges a short-load fee before assuming bulk is cheaper.
Depth by job
A vegetable bed wants 6 to 8 inches of workable soil, which on unamended ground means tilling in 3 to 4 inches of compost rather than dumping 8 inches of loam on top. A new lawn needs 4 to 6 inches of topsoil before seed or sod, blended into the existing grade rather than laid as a layer, or the grass roots will refuse to cross the boundary.
Mulch beds are 2 to 3 inches. More than 3 inches starves the soil underneath of air and water, and piling mulch against a trunk or foundation invites rot and pests. Leveling a low spot is usually 1 to 2 inches, but if the dip is deeper than that, the cause is drainage and more soil will not fix it.
What to ask before you order
Screened versus unscreened is the first question. Unscreened fill is cheap and full of rocks, roots and clay clods. Screened topsoil costs 30 to 50 percent more and is what you want for a lawn or a bed. Ask what the organic matter content is and whether the soil has been tested; some yards sell blends that are largely sand and compost, which drains fast and dries out.
Second question is where the truck can drop it. A pile on the driveway means every wheelbarrow load is a round trip. Paying for a conveyor or a smaller dump trailer to place it near the bed is often cheaper than a weekend of hauling.
Frequently asked questions
How many cubic yards of topsoil do I need for a 20x10 bed?
About 2 cubic yards at 3 inches deep, once a 15 percent settle allowance is added. The bed itself is 1.85 yards; you order 2.1 and spread it slightly proud of the final grade.
How much does a cubic yard of topsoil weigh?
Roughly 1.1 tons, or 2,200 pounds, when screened and moderately moist. Wet loam is heavier, dry screened loam lighter. A half-ton pickup should not carry a full yard.
How many bags of topsoil are in a yard?
Thirteen and a half 2 cubic foot bags, or 27 1 cubic foot bags. Bagged soil costs three to four times as much per yard as bulk delivery.
How deep should topsoil be for a new lawn?
Four to six inches, tilled into the existing soil rather than laid on top as a separate layer. Grass roots will not cross a sharp texture boundary, which is why a thin layer over hard subsoil fails.
Do I need to add extra for settling?
Yes for topsoil, compost and anything loose and organic — 15 to 20 percent is typical. No for bark mulch, which is supposed to stay coarse and does not compact the same way.
Can I use this calculator for mulch?
Yes. Choose bark mulch, set the settle allowance to zero, and use 3 inches of depth. Mulch is lighter — about 0.45 tons per cubic yard — so a yard covers far more area per ton than soil.
What is the difference between topsoil and fill dirt?
Topsoil has organic matter and supports plant growth. Fill dirt is subsoil, often with clay or rock, and is used only to change grade. Fill is much cheaper and will not grow anything until it is capped with topsoil.
Disclaimer: This calculator estimates volume from bed dimensions and a typical bulk density. Actual settling, moisture content and supplier measures vary. Confirm yardage and delivery terms with the supplier before ordering.
Citing this page? FigureMill, “Topsoil Calculator” (last reviewed October 31, 2026). Topsoil, compost or mulch volume in cubic yards, bags and tons from bed dimensions, with a settle allowance. https://figuremill.com/materials/topsoil-calculator
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