How Much Topsoil Do I Need? Depth Guide by Project
Quick answer: You need 2 inches of topsoil for leveling, 4--6 inches for a new lawn, 4--6 inches for garden beds, and 1 inch for overseeding. One cubic yard covers about 162 sq ft at 2 inches deep. Punch in your exact area and depth in the topsoil calculator to get cubic yards and cost.
Every spring I see the same question in every gardening forum: "I have a 20x30 area, how much topsoil do I order?" And every answer is some variation of "it depends on the project." Which is true but completely useless without the actual numbers.
So here are the actual numbers. Depth by project type, volume by area, and what it'll cost.
Recommended Topsoil Depth by Project
This is the table I wish I'd had before my first landscaping project. I spread 1 inch of topsoil over a new lawn area, seeded it, and watched the grass come up patchy and thin. The soil was too shallow for the roots to establish properly.
| Project Type | Recommended Depth | Cu Yd per 100 sq ft | Cu Yd per 1,000 sq ft | Notes |
|---|---|---|---|---|
| New lawn (from seed) | 4--6 inches | 1.2--1.9 | 12.3--18.5 | Deeper = better root establishment |
| New lawn (from sod) | 4 inches min | 1.2 | 12.3 | Sod needs firm contact with soil beneath |
| Overseeding existing lawn | 0.5--1 inch | 0.15--0.3 | 1.5--3.1 | Thin layer to cover seed and improve contact |
| Leveling / grading a yard | 2--4 inches (varies) | 0.6--1.2 | 6.2--12.3 | Depends on how uneven the ground is |
| Raised garden beds | 10--12 inches | 3.1--3.7 | -- | Mixed with compost and amendments |
| Flower beds | 4--6 inches | 1.2--1.9 | -- | Tilled into existing soil |
| Topdressing lawn | 0.25--0.5 inch | 0.08--0.15 | 0.8--1.5 | Screened topsoil only, applied annually |
| Tree and shrub planting | 6--8 inches around root zone | varies | -- | Mix 50/50 with existing soil |
How to Calculate Your Exact Volume
The formula is straightforward:
Length (ft) x Width (ft) x Depth (inches) / 324 = cubic yards
That 324 is the magic number -- it converts square feet and inches into cubic yards in one step. Or if you prefer two steps:
- Length x Width x (Depth / 12) = cubic feet
- Cubic feet / 27 = cubic yards
Example: You're putting in a new lawn on a 30x40 foot area at 4 inches of topsoil.
30 x 40 x 4 / 324 = 14.8 cubic yards
At $30--$50 per cubic yard delivered, that's $444--$740. Not cheap, but skimping on topsoil depth for a new lawn is a false economy -- you'll spend more on reseeding bare patches and extra watering than you saved on soil.
Cost Estimates by Project Size
Here's what real-world topsoil projects cost. Bulk topsoil runs $25--$50 per cubic yard depending on quality and your location. Delivery is typically $30--$75 per load.
| Project | Area | Depth | Volume | Estimated Cost |
|---|---|---|---|---|
| Level a small yard area | 200 sq ft | 2" | 1.2 cu yd | $60--$110 |
| New flower bed | 100 sq ft | 6" | 1.9 cu yd | $75--$145 |
| Overseed a lawn | 2,000 sq ft | 0.5" | 3.1 cu yd | $120--$205 |
| New lawn (seed) | 1,000 sq ft | 4" | 12.3 cu yd | $400--$690 |
| New lawn (seed) | 2,000 sq ft | 4" | 24.7 cu yd | $770--$1,310 |
| Fill 3 raised beds (4x8) | 96 sq ft | 12" | 3.6 cu yd | $140--$230 |
What Type of Topsoil to Buy
Not all topsoil is equal. Here's what to ask for:
Screened topsoil -- this has been run through a screen to remove rocks, roots, and debris. It's what you want for lawns, gardens, and raised beds. Costs $30--$50 per cubic yard. If a yard just says "topsoil" without "screened," ask. Unscreened topsoil can be full of rocks and clay chunks.
Unscreened topsoil -- cheaper ($20--$35/cu yd) but full of rocks, roots, and inconsistency. Fine for filling low spots that will be covered or as a base layer under screened topsoil. Not good for direct planting.
Enriched / garden blend topsoil -- topsoil pre-mixed with compost. Usually 70/30 or 60/40. Costs $40--$65 per cubic yard. Good for garden beds and flower beds where you'd be adding compost anyway. Not necessary for lawns.
Pulverized topsoil -- finely ground, good for topdressing and overseeding. Spreads more evenly on an existing lawn. Costs $35--$55 per cubic yard.
Quick quality test: grab a handful and squeeze. Good topsoil holds together loosely when damp, then crumbles when you poke it. If it stays in a hard ball, it's too much clay. If it falls apart immediately, it's too sandy.
How Much Extra Should I Order?
Always order 10--15% more than your calculated volume. Here's why:
Settling. Fresh topsoil settles 10--15% after the first few waterings. If you order exactly 12.3 cubic yards for your new lawn, you'll end up with 10.5--11 cubic yards of effective coverage once it settles.
Ground isn't level. Your calculation assumes a perfectly flat surface. In reality, there are dips and variations that eat extra volume. I've had projects where "2 inches of topsoil" over an uneven lawn required 30% more than calculated to get consistent coverage.
Waste. Some soil spills off the edges, some stays in the wheelbarrow, some ends up in places you didn't plan. Not a lot, but 3--5% disappears to inefficiency.
Leftover is useful. Extra topsoil never goes to waste. Spread it on thin spots, add it to garden beds, use it for patching. Leftover is a minor inconvenience. Running short mid-project means another delivery fee.
Common Mistakes That Waste Soil (and Money)
Not removing existing sod before adding topsoil for a new lawn. If you dump topsoil on top of existing grass, the dead grass creates a layer that blocks root growth and drainage. Remove the old sod first, or at minimum kill it with a non-selective herbicide 2 weeks before adding topsoil.
Spreading topsoil too thick for overseeding. I did this -- put down 2 inches over my existing lawn before overseeding. The existing grass smothered and died. For overseeding, you want a quarter to half inch max. Just enough to cover the seed and improve soil contact.
Ordering the wrong type. A neighbor ordered 5 cubic yards of "topsoil" for a new flower bed. What arrived was essentially fill dirt -- clay-heavy subsoil with no organic matter. The vendor's website said "topsoil." She had to order compost separately and till it in. Ask for screened topsoil and specify the purpose.
Ignoring drainage. Adding 6 inches of topsoil to a low spot without addressing the drainage problem underneath just creates a soggy area 6 inches higher. If water pools there now, it'll pool on top of your new topsoil too. Grade the area so water flows away before adding soil.
Topsoil vs Other Soil Types
People use "topsoil," "garden soil," and "dirt" interchangeably. They're not the same thing.
Topsoil is the upper layer of native earth, typically the top 4--12 inches. It has organic matter, microorganisms, and nutrients. It's the base of any planting project.
Garden soil is topsoil enriched with compost and amendments. It's ready to plant in. Better for beds, overkill for lawns (and more expensive).
Compost is decomposed organic material. It's not a standalone planting medium -- it's an amendment you mix into topsoil. Pure compost retains too much moisture and can burn plant roots.
Fill dirt is subsoil from excavation. No nutrients, no organic matter. For grading and filling, not for growing things.
I wrote a full comparison in topsoil vs garden soil vs compost if you want the deep dive on when to use which.
FAQ
How many cubic yards of topsoil do I need for 1,000 square feet?
At 2 inches deep: 6.2 cubic yards. At 4 inches deep: 12.3 cubic yards. At 6 inches deep: 18.5 cubic yards. The formula is (area in sq ft x depth in inches) / 324 = cubic yards. Add 10--15% for settling and ground variations. Use the topsoil calculator for instant results.
How deep should topsoil be for grass seed?
Four to six inches for a new lawn from seed. This gives roots enough depth to establish before summer heat. For overseeding an existing lawn, you only need 0.25--0.5 inches of topsoil spread over the seed. Going deeper on an overseed will smother the existing grass.
How much does a cubic yard of topsoil weigh?
A cubic yard of topsoil weighs roughly 2,000--2,200 lbs when moderately damp. Dry topsoil is lighter (1,600--1,800 lbs). Wet, heavy topsoil can push 2,400+ lbs. This matters for delivery and for your truck if you're picking it up yourself -- don't load more than your vehicle's rated payload.
Can I just put topsoil over clay and plant?
You can, but roots will hit the clay layer and struggle. For best results, till the topsoil into the top few inches of clay to create a transition zone. If you just layer topsoil on top of clay, water will pool at the interface between the two layers (perched water table effect). Four inches of topsoil tilled into 2 inches of clay is better than 6 inches of topsoil sitting on top of untouched clay.
Next Steps
- Get your exact volume with the topsoil calculator -- enter your area dimensions and desired depth for instant cubic yards and cost estimates.
- For raised beds, use the soil volume calculator instead -- it's tuned for bed dimensions and gives you bag counts.
- Need to cover the topsoil with mulch? The mulch calculator will tell you exactly how much to order.