The Topsoil Calculator converts area and depth into the volume and weight of topsoil needed for a new lawn, a garden bed, a raised bed or a general fill job. Three blends are built in, screened topsoil, a compost garden mix, and unscreened fill dirt, each with its own bulk density. Settling and waste allowances apply on top of the geometric volume, since a freshly spread layer of topsoil compresses once it is watered and walked on.
Calculate topsoil volume for a bed or lawn
Topsoil volume is area multiplied by depth, the same starting point as gravel or mulch, but the depth needed varies more by application than either of those materials does. A lawn top-dressing and a raised bed fill can call for a fourfold difference in depth on the same footprint.
Volume (ft³) = Area (ft²) × Depth (ft)
Volume (yd³) = Volume (ft³) ÷ 27Enter the area directly, or build it from a rectangle, circle or other shape the way any of the area-based calculators on this site do. Depth goes in inches for anything under a foot, since that is how topsoil depth is almost always specified on a bag or a supplier's recommendation sheet.
Choose a topsoil blend
Blend changes bulk density and, with it, the weight of a given volume, which matters once an order needs to be converted to a delivery weight rather than a yardage. The three blends built into the calculator cover most residential jobs.
| Blend | Density |
|---|---|
| Screened topsoil | 2,000 lb/yd³ |
| Compost garden mix | 1,200 lb/yd³ |
| Unscreened fill dirt | 2,200 lb/yd³ |
Screened topsoil has been passed through a screen to remove rocks, roots and clumps, and is the standard choice for a lawn or a bed that will be planted directly. Compost garden mix is lighter and richer in organic matter, suited to vegetable beds where nutrient content matters more than a fine, uniform texture. Unscreened fill dirt is the heaviest of the three and the cheapest, appropriate for grading and filling low spots where nothing will be planted directly into it and a smooth finish is not required. Structural fill beneath a slab or a patio uses unscreened material for the same reason: it is not going to grow anything.
Apply the topsoil volume formula
The arithmetic is identical to any other area-times-depth material: convert depth to feet, multiply by area, then divide by 27 for cubic yards. The only variable that changes from job to job is which depth applies, covered in the application table below.
Depth (ft) = Depth (in) ÷ 12
Volume (ft³) = Area (ft²) × Depth (ft)
Volume (yd³) = Volume (ft³) ÷ 27A 300 ft² bed at 6 inches of screened topsoil needs 6 ÷ 12 = 0.5 ft of depth, then 300 × 0.5 = 150 ft³, then 150 ÷ 27 = 5.56 yd³ before any settling allowance is added. The formula does not change between blends; only the density used to convert that volume into a delivery weight does.
Estimate topsoil to patch a 6' × 4' lawn area
A bare patch measuring 6 ft by 4 ft, filled 2 inches deep to level it before reseeding, needs 4.0 cubic feet of topsoil, or about 0.15 cubic yards. Every step below shows the units carried through. 1. Find the patch area. 6 ft × 4 ft = 24 ft²
2. Convert the depth to feet. 2 in ÷ 12 = 0.167 ft
3. Find the volume in cubic feet. 24 ft² × 0.167 ft = 4.0 ft³
4. Convert to cubic yards. 4.0 ft³ ÷ 27 = 0.15 yd³
A patch this small is well below any bulk delivery minimum, and a single 1 ft³ bag with material left over covers it. Scaling the same 2-inch fill depth up to a 1,000 ft² lawn low spot changes the answer to 1,000 × 0.167 = 166.7 ft³, or 6.17 cubic yards, the point at which bulk delivery becomes the practical choice.
Match soil depth to the application
Depth is set by what will grow in the topsoil or what the fill is supporting, and using the wrong depth either starves roots of room or wastes material that adds nothing at the surface. Four applications cover nearly every residential job.
| Application | Depth |
|---|---|
| Lawn establishment | 4 in |
| Garden beds | 6 in |
| Raised beds | 8 in |
| Fill / leveling | 2 in |
A new lawn seeded or sodded over 4 inches of screened topsoil gives grass roots enough loose material to establish before hitting the compacted subgrade beneath. A vegetable or flower bed benefits from the extra 2 inches that garden-bed depth provides, since deeper roots and denser planting draw on a larger volume of soil. Raised beds go deepest of all at 8 inches because the bed itself is the entire root zone, with no native soil beneath it to draw on. Fill and levelling work uses the shallowest depth on the table, since the goal is correcting a grade rather than building a growing medium.
Allow for settling and compaction
Topsoil settles after it is spread, watered and walked on, typically losing volume as air pockets between clumps close up, and the geometric volume calculated from area and depth consistently under-orders as a result.
A default settling allowance of 15 percent, plus a separate 15 percent waste allowance for spillage and an uneven subgrade, together account for the gap between the calculated volume and what actually needs to be ordered.
Order volume = Geometric volume × (1 + settling%) × (1 + waste%)A 1,000 ft² lawn topped with 4 inches of screened topsoil has a geometric volume of 1,000 × (4 ÷ 12) = 333.3 ft³, or 12.35 cubic yards. Applying the default 15 percent settling and 15 percent waste allowances brings the order to 12.35 × 1.15 × 1.15 = 16.33 cubic yards, roughly a third more than the raw geometry suggests. Skipping this step is the most common reason a topsoil delivery falls short once the material is spread and watered in.
Decide between bags and bulk delivery
Bagged topsoil is priced for convenience and small jobs; bulk delivery is priced for volume and becomes the cheaper option well before a full cubic yard is reached. Four bag sizes are standard: 0.75, 1, 1.5 and 2 cubic feet.
A cubic yard takes 36 bags at 0.75 ft³, 27 bags at 1 ft³, 18 bags at 1.5 ft³, or roughly 14 bags at 2 ft³. Below about a quarter of a cubic yard, most suppliers' delivery minimums push the practical choice toward bags even though the per-unit cost is higher. A dump truck load, typically several cubic yards at once, is the other end of the scale, appropriate once a job clears several yards and carrying dozens of bags by hand stops being reasonable.
Frequently asked questions
How much topsoil do I need for a new lawn?
Use 4 inches of depth across the lawn area. A 1,000 ft² lawn at 4 inches needs 1,000 × (4 ÷ 12) = 333.3 ft³, or 12.35 cubic yards, before the settling and waste allowances are added.
What is the difference between topsoil and garden soil?
Screened topsoil is native soil cleaned of rocks and debris, with a density around 2,000 lb/yd³. A compost garden mix is lighter, at around 1,200 lb/yd³, and blends organic matter in for nutrient content, making it better suited to vegetable beds than a straight topsoil fill.
How many bags of topsoil equal a cubic yard?
Thirty-six bags at 0.75 ft³, 27 bags at 1 ft³, 18 bags at 1.5 ft³, or about 14 bags at 2 ft³. Check the printed cubic-foot volume on the bag, since bag sizes are not standardised across suppliers.
How deep should topsoil be for a raised bed?
Eight inches is the standard depth for a raised bed, since the bed itself makes up the entire root zone with no native soil underneath to supplement it. A vegetable garden built into the ground rather than a raised frame needs less, around 6 inches.
Does topsoil settle after it is spread?
Yes. Freshly spread topsoil typically loses around 15 percent of its volume as it settles from watering and foot traffic, which is why the calculator applies a settling allowance on top of the geometric volume by default.
Is bagged or bulk topsoil cheaper?
Bulk is cheaper per cubic yard almost always, but bagged topsoil avoids a delivery minimum on small jobs. Below roughly a quarter of a cubic yard, bags are usually the more practical choice even at a higher per-unit price.
Can topsoil be used to fill low spots in an existing lawn?
Yes, at the fill and levelling depth of about 2 inches per application. Filling a low spot deeper than a couple of inches in one pass can smother the existing grass; larger depressions are better corrected in more than one thin layer over successive seasons.
How much does a cubic yard of topsoil weigh?
About 2,000 lb for screened topsoil, 1,200 lb for a compost garden mix, or 2,200 lb for unscreened fill dirt. Multiply the cubic-yard volume by the blend's density to estimate delivery weight for trucks or trailers with a load limit.
What is unscreened topsoil, and when should it be used?
Unscreened fill dirt has not been passed through a screen to remove rocks, roots and clumps, making it heavier, at about 2,200 lb/yd³, and cheaper than screened topsoil. Use it for grading and structural fill where nothing is being planted directly, not for a bed or lawn surface.
How much topsoil do I need to raise an entire yard's grade by a couple of inches?
Multiply the total yard area by the target depth increase, in feet, then divide by 27 for cubic yards, and add the settling and waste allowances since a large, thin layer is prone to both. A 2,000 ft² yard raised by 2 inches needs 2,000 × (2 ÷ 12) ÷ 27 = 12.35 cubic yards geometric, before allowances.
Summary
The Topsoil Calculator turns area and depth into cubic yards and weight, using screened topsoil, compost garden mix or unscreened fill dirt, each with its own density. Depth is set by application: 4 inches for a new lawn, 6 for garden beds, 8 for raised beds, and 2 for fill and levelling.
A default 15 percent settling allowance plus a 15 percent waste allowance account for the gap between geometric volume and what actually needs to be ordered once topsoil is spread and watered in. Bags cover small jobs under about a quarter of a yard; bulk delivery is cheaper for anything larger.