Topsoil Calculator

Calculate how much topsoil you need in cubic yards, tons and 40 lb bags for a new lawn, raised bed or top-dressing. Enter the area and soil depth.

By CalcBuilt Editorial TeamUpdated September 9, 2026Formulas checked against manufacturer specs, see how we calculate.

Quick answer: To find how much topsoil you need, multiply length by width by depth in feet and divide by 27 for cubic yards. A 20 x 10 ft area filled 6 in deep needs 3.7 cubic yards, which weighs about 4.07 tons or works out to 134 bags of 40 lb topsoil.

Results

Topsoil needed: 3.7 cu yd; 100 cu ft
Weight: 4.07 tons; 8,148 lb at about 1.1 tons per cubic yard
40 lb (18 kg) bags: 134 bags; About 0.75 cu ft per bag
Area covered: 200 sq ft; At 6 in deep

Topsoil formula

Cubic feet = Length (ft) x Width (ft) x Depth (in) / 12
Cubic yards = Cubic feet / 27
Tons = Cubic yards x 1.1
40 lb bags = Cubic feet / 0.75

Worked example

A 30 x 15 ft lawn area that needs 4 in of new topsoil: 30 x 15 x (4 / 12) = 150 cubic feet. 150 / 27 = 5.56 cubic yards. At 1.1 tons per yard that is about 6.1 tons, so order 6 yards in bulk. At $35 per yard the soil costs about $194 plus delivery.

In bags: 150 / 0.75 = 200 bags of 40 lb topsoil. At that quantity a bulk delivery is far cheaper and saves a lot of lifting.

Quick reference

Topsoil needed per 1,000 sq ft by depth
Depth	Cubic feet	Cubic yards	Tons
2 in	167	6.17	6.79
3 in	250	9.26	10.19
4 in	333	12.35	13.58
6 in	500	18.52	20.37
8 in	667	24.69	27.16
12 in	1,000	37.04	40.74

How to calculate topsoil

Multiply the length by the width in feet to get the area, then multiply by the depth in feet (inches divided by 12) for cubic feet. Divide by 27 to convert to cubic yards, which is how bulk suppliers sell it. A 20 by 10 foot area at 6 inches deep is 100 cubic feet, or 3.7 cubic yards.

Suppliers often quote by the ton as well. Screened topsoil weighs roughly 1.1 tons per cubic yard when moderately moist. A load from an uncovered pile after rain can weigh 1.4, so a ton buys less soil in wet weather. Loose screened soil settles 15 to 20 percent once it is spread, watered and walked on. For a new lawn, order 20 percent more than the result: 6 in spread loose settles to about 5 in, and the sod or seed still needs the full depth.

How deep should topsoil be?

For a new lawn, spread 4 to 6 inches of topsoil over the graded subsoil before seeding or laying sod. Loosen the top 2 to 3 inches of subsoil with a tiller first; topsoil laid on a smooth, compacted subgrade creates an interface where roots stop and water perches. Grade the finished soil about 1 inch below walks and driveways so sod sits flush. For vegetable gardens and raised beds, 8 to 12 inches gives roots room, and a 70/30 topsoil and compost blend is the usual garden mix. To top-dress a thin lawn, rake in no more than 1/2 inch at a time so the grass can grow through it.

Bagged topsoil at typically $2 to $4 per 40 lb bag makes sense for a few beds or planters. At 36 bags per yard that is $70 to $140 against $25 to $55 bulk, so bulk wins past about a yard even with a delivery fee. A single-axle dump truck carries 5 to 7 yards of soil and a tri-axle 10 to 14, and the delivery fee is the same for 3 yards as for 12. A half-ton pickup is rated for about half a yard: a full yard of damp soil weighs 2,200 lb or more and exceeds its payload.

What this calculator leaves out

Screening. The word topsoil is not regulated, so ask. Screened soil has gone through a 1/2 or 3/4 in screen that removes rocks, roots and clods. Unscreened soil is a site strip and comes with all of them plus whatever weed seed was growing there. Grab a handful from the pile: it should crumble, not smear like clay. The result also leaves out the settling allowance, the compost or lime a soil test calls for, and starter fertilizer.

Delivery. A loaded tri-axle weighs 50,000 lb or more and needs about 12 ft of width and 14 ft of overhead clearance. It raises its bed to roughly 20 ft to dump and drops everything in one pile where it stops. Stage the pile on the driveway on a tarp, not on the lawn or over a septic field, and plan about one hour per yard to move it by wheelbarrow.

Mistakes that cost money

Unscreened topsoil comes with clods, rocks and a season of weed seed; buy soil screened through a 1/2 or 3/4 in screen.
No settling allowance: 6 in of loose soil settles to about 5 in; order 15 to 20 percent more and roll before final grade.
Tri-axle dumped on the lawn: 50,000 lb ruts the yard, crushes septic lines, and the whole load lands in one pile where the truck stops.
Wires or branches under 20 ft over the drop spot: the raised bed cannot clear them, so the driver dumps at the street.
Topsoil spread over compacted, smooth subsoil: roots stop and water perches at the interface; till the top 2 to 3 in of subgrade first.
A full yard in a half-ton pickup: damp soil at 2,200 lb or more exceeds the payload; haul half a yard per trip.

Key facts

One cubic yard of topsoil weighs about 2,000 to 2,200 lb dry and can reach 3,000 lb when saturated.
One cubic yard covers 162 sq ft at 2 in deep, 81 sq ft at 4 in, and 54 sq ft at 6 in.
A 40 lb bag of topsoil holds about 0.75 cubic feet, so 36 bags make one cubic yard.
A new lawn from seed or sod needs at least 4 to 6 in of good topsoil for healthy roots.
Top-dressing an existing lawn uses only 1/4 to 1/2 in of screened soil or compost per application.

Frequently asked questions

How much does a cubic yard of topsoil weigh?

About 2,000 to 2,200 pounds when dry and moderately moist, or roughly 1.1 tons. Wet soil can weigh 3,000 pounds or more per yard.

How many bags of topsoil are in a cubic yard?

About 36 bags of 40 lb topsoil, since each bag holds roughly 0.75 cubic feet and a cubic yard is 27 cubic feet.

What is the difference between screened topsoil, unscreened topsoil and fill dirt?

Screened topsoil has been run through a 1/2 or 3/4 in screen to remove rocks, roots and clods, and is what goes under a lawn or in beds. Unscreened topsoil is the same pile before screening and costs about half, but you sort the rocks and pull the weeds. Fill dirt is subsoil with little organic matter; it raises grade under the topsoil and grows nothing.

How much topsoil do I need for a new lawn?

Plan on 4 to 6 inches over the whole area. A 1,000 square foot lawn at 4 inches needs about 12.4 cubic yards settled, so order about 15 yards to allow for settling.

Sources and references

Lawn Establishment (topsoil depth for new turf) (Penn State Extension)
Seeding and sodding home lawns (University of Minnesota Extension)
How to Use Compost in Gardens and Landscapes (EM 9308), calculating soil volume by area and depth (Oregon State University Extension)

Next steps for this project

The usual order for a landscaping & outdoor project. See all landscaping & outdoor calculators.

Results are estimates based on standard formulas and typical product specifications. Confirm quantities with your supplier and local code before ordering.