at the chosen size
RecommendedTopsoil Units: Yards, Feet, Bags and Tons
Topsoil is quoted in cubic yards by bulk suppliers, in cubic feet on bags, and sometimes in tons when it crosses a scale. All three describe the same material, and moving between them is straightforward as long as the depth is converted from inches to feet first.
A cubic yard is 27 cubic feet. Screened topsoil weighs roughly 1.1 tons per cubic yard, but that figure moves more than any other conversion on this page, because soil holds water. Dry screened soil can come in under a ton per yard, and the same soil after heavy rain can approach 1.4 tons. Order by volume where possible, and treat any tonnage conversion as an estimate.
Core formulaArea in square feet x (depth in inches divided by 12) = cubic feet, divided by 27 = cubic yards, multiplied by 1.1 = approximate tons
Convert depth to feet before multiplying. Four inches is 0.3333 feet, 6 inches is 0.5 feet, 12 inches is 1 foot.
A Worked Example: 1,200 sq ft of New Lawn at 4 Inches
Take a bare area of 1,200 square feet being prepared for new lawn with 4 inches of topsoil.
- Convert depth: 4 divided by 12 equals 0.3333 feet.
- Volume: 1,200 x 0.3333 equals 400 cubic feet.
- Cubic yards: 400 divided by 27 equals 14.81 cubic yards.
- Add 10 percent for settling and spread: 14.81 x 1.10 equals 16.3 cubic yards.
- Approximate weight: 16.3 x 1.1 equals about 17.9 tons.
In bags, 400 cubic feet at 1.5 cubic feet per bag is 267 bags before any allowance. That number alone answers the bagged versus bulk question for a job this size.
How Deep Should Topsoil Be?
- 2 to 3 inches: topdressing an existing lawn to level low spots and add organic matter. Never bury living grass entirely, so apply thinly and rake it into the sward.
- 4 to 6 inches: a new lawn from seed or sod. This is the working root zone for turf, and it is where most lawn failures are actually decided.
- 6 to 12 inches: planting beds for perennials and shrubs, depending on what is going in and what is already underneath.
- 10 to 12 inches: raised beds for vegetables. Deeper is fine, but 10 to 12 inches of good soil supports most crops, and shallow beds dry out quickly.
Depth matters more than quality up to a point. Four inches of average screened topsoil over loosened subsoil grows better turf than 2 inches of premium blend over compacted clay. If the ground underneath is compacted, break it up before importing soil, or the new layer becomes a shallow container sitting on a hardpan.
Raised Bed Soil Blends
Straight topsoil in a raised bed compacts and drains poorly. Raised beds want a blend. A common and reliable recipe is 60 percent screened topsoil, 30 percent compost and 10 percent aeration material such as perlite or coarse sand.
For a 4 ft by 8 ft bed filled 12 inches deep, the volume is 4 x 8 x 1, or 32 cubic feet, about 1.19 cubic yards. Split at 60, 30 and 10 percent, that is 19.2 cubic feet of topsoil, 9.6 cubic feet of compost and 3.2 cubic feet of perlite or coarse sand. Buying those as separate bulk or bagged components almost always costs less than a pre mixed raised bed soil.
Two cautions on the aeration component. Fine sand mixed into clay heavy topsoil makes something closer to concrete than to soil, so use coarse sand or perlite. And compost above about 30 to 40 percent of the mix holds too much water and slumps heavily as it breaks down, leaving the bed several inches low within a season.
Topsoil, Garden Soil, Potting Mix and Fill Dirt
MaterialWhat It IsBest UseTypical Depth or Note
Screened topsoilNative surface soil run through a screen to remove rock and debrisLawns, regrading, bulk bed filling4 to 6 in for lawns
Garden soilTopsoil already blended with compost and organic matterPlanting beds and borders6 to 12 in
Raised bed mixTopsoil, compost and an aeration material blended for containersRaised beds and large planters10 to 12 in
CompostFully broken down organic matter, no mineral soilAmendment and topdressing, not a standalone growing mediumKeep under about 30 percent of a blend
Potting mixPeat or coir with perlite and bark, usually soillessContainers and seed starting onlyToo light and too costly for beds
Fill dirtSubsoil with little organic matter, often unscreenedFilling holes, building grade, backfillNothing grows well in it
The important distinction is between fill dirt and topsoil. Fill dirt is a structural material used to build up grade, and it is cheaper for good reason. Using it as a growing medium produces poor drainage and thin, struggling plants. Conversely, using topsoil to build up a large grade change is expensive and unnecessary. A common approach is fill dirt to build the grade, then 4 to 6 inches of topsoil on top.
Settling and Why to Order Extra
Delivered topsoil is loose and full of air pockets from screening and handling. Once it is spread, raked, watered and rained on, it settles. Ten percent is a reasonable general allowance, and 15 to 20 percent is safer for raised beds and anywhere with a high compost content, since organic matter continues breaking down and losing volume for months.
Raised beds in particular drop noticeably in the first season. Filling a bed level to the rim in spring and finding it 2 inches low by fall is normal, not a delivery shortfall. Overfilling slightly with a slight crown, then topping up the following season, is standard practice.
Coverage rule of thumbOne cubic yard of topsoil covers about 108 square feet at 3 inches, 81 square feet at 4 inches, and 54 square feet at 6 inches. Divide the area by those figures to check any order before it is placed.
Bagged Sizes and When Bags Make Sense
Bagged topsoil is commonly sold in 1, 1.5 and 2 cubic foot bags. That means 27, 18 or 13.5 bags per cubic yard respectively. Bags suit small jobs: filling a couple of containers, patching low spots in a lawn, topping up a single raised bed, or any site a truck cannot reach.
Bulk becomes the better deal quickly, usually somewhere around 10 to 15 bags, and it is the only realistic option past a cubic yard or so. Bulk delivery brings minimum order quantities, typically 1 to 3 cubic yards, plus a delivery fee and the need for somewhere to dump the pile. Weight matters when self hauling: at about 1.1 tons per cubic yard, a half ton pickup is at its limit at roughly one cubic yard of screened topsoil, and less if the soil is wet.
Testing What Is Already There
Importing soil is worth doing only if what is there is genuinely inadequate. Two simple checks answer that.
The jar test shows texture. Fill a straight sided jar about one third with soil, top up with water, add a drop of dish soap, shake hard and let it stand. Sand settles within a minute, silt over a few hours, clay over a day or more. The relative band thicknesses show the proportions. A loam, roughly 40 percent sand, 40 percent silt and 20 percent clay, is the target.
The percolation test shows drainage. Dig a hole about 12 inches deep and 12 inches across, fill it with water, let it drain completely, then fill it again and time the second drain. Roughly 1 to 3 inches per hour is good. Much slower indicates compaction or heavy clay, and importing topsoil on top of that without loosening it first will not fix the problem.
A soil test through a local extension service adds pH and nutrient levels for a modest fee. In many cases the result shows that amending and aerating the existing soil is a better investment than trucking in a new layer.