Field Guide
How Much Topsoil Do I Need? Lawns, Gardens & Raised Beds
Whether you're seeding a new lawn, building raised beds, or filling a low spot, the math is the same: measure the area, pick a depth, convert to cubic yards, and add a little extra for settling.
1. How to Calculate Topsoil (The Math Explained)
Bulk topsoil is sold by the cubic yard; bagged soil by the cubic foot. Here's the exact process this calculator uses.
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1
Find the area and convert depth to feet
Multiply length by width in feet (or use π × radius² for a round bed). Divide the depth in inches by 12.
Area = 40 ft × 30 ft = 1,200 sq ft Depth = 4 in ÷ 12 = 0.333 ft -
2
Multiply for cubic feet, then add settling
Loose soil settles after it's spread, raked and watered. A 10% allowance keeps the finished grade where you want it.
Cubic Feet = 1,200 × 0.333 = 400 ft³ With 10% settling = 400 × 1.10 = 440 ft³ -
3
Convert to cubic yards (and bags)
Divide by 27 for cubic yards. For bags, divide cubic feet by the bag size and round up.
Cubic Yards = 440 ÷ 27 = 16.30 yd³ 0.75 cu ft bags = 440 ÷ 0.75 = 586.7 → 587 bags -
4
Estimate the weight
Weight matters if you're hauling it yourself. Dry screened topsoil runs about 75 lbs per cubic foot, roughly a ton per cubic yard.
Pounds = 440 ft³ × 75 lbs/ft³ = 33,000 lbs Tons = 33,000 ÷ 2,000 = 16.5 tons (dry)
Quick topsoil conversions
- 1 cubic yard = 27 cubic feet
- 1 cubic yard covers 324 sq ft at 1 in, 162 sq ft at 2 in, or 81 sq ft at 4 in
- 1 cubic yard ≈ 36 bags of 0.75 cu ft, or 27 bags of 1 cu ft
- 1 cubic yard of dry topsoil weighs about 1 ton; moist soil weighs 20–40% more
2. Topsoil vs. Garden Soil vs. Fill Dirt
Ordering the wrong soil is an expensive mistake: fill dirt under a lawn grows poor grass, and premium garden mix is wasted filling a hole. These are typical dry, loose weights; every supplier's blend is a little different.
| Material | Lbs / ft³ | Tons / yd³ | Best uses |
|---|---|---|---|
| Screened Topsoil | ≈ 75 | 1.01 | New lawns, grading and leveling. Screened to remove rocks and roots. |
| Garden Soil / Blend | ≈ 65 | 0.88 | Topsoil mixed with compost: flower beds, vegetable gardens, raised beds. |
| Compost | ≈ 40 | 0.54 | Mixing into beds and top-dressing lawns. Not a soil on its own. |
| Fill Dirt | ≈ 80 | 1.08 | Filling holes, low spots and backfill. Subsoil with little organic matter, so cap it with topsoil before planting. |
3. How Deep Should Topsoil Be?
Roots need room. Too thin and new grass dries out and thins; too thick over existing grass and you smother it. Use these starting points.
¼–½ in
Lawn Top-Dressing
A thin layer of compost or screened topsoil raked into existing grass, often after aerating. Never bury the grass blades.
4–6 in
New Lawns & Sod
Spread over loosened subsoil before seeding or laying sod. Go to 6 in over heavy clay or rocky ground.
6–8 in
Flower & Shrub Beds
Garden soil blend worked into the existing soil. Shrubs need a wider planting area, not just a deeper one.
8–12 in
Vegetable Gardens & Raised Beds
Most vegetables root in the top 12 in. Fill raised beds to the rim; they settle an inch or two the first season.
Pro tip: fill low spots in layers
For holes and low areas deeper than a few inches, use fill dirt for the bottom and finish with 4–6 in of topsoil. Spread and tamp or water in 2–4 in layers so the area doesn't sink later.
4. Frequently Asked Questions
How much area does a cubic yard of topsoil cover?
One cubic yard (27 cubic feet) covers:
- 1 in deep: 324 sq ft
- 2 in deep: 162 sq ft
- 3 in deep: 108 sq ft
- 4 in deep: 81 sq ft
- 6 in deep: 54 sq ft
Add about 10% for settling when you order.
How much does a cubic yard of topsoil weigh?
Dry screened topsoil weighs about 1 ton (2,000 lbs) per cubic yard. This calculator uses 75 lbs per cubic foot, or about 2,025 lbs per yard. Moist soil can weigh 20–40% more, so plan pickup loads on the heavy side.
How many bags of topsoil make a cubic yard?
A cubic yard is 27 cubic feet, so it takes 36 bags of 0.75 cu ft, 27 bags of 1 cu ft, or 18 bags of 1.5 cu ft. Past about one cubic yard, bulk delivery is usually much cheaper.
How much topsoil do I need for a new lawn?
Plan on 4–6 in of topsoil over loosened subsoil. For 1,000 sq ft at 4 in, that's 333 cubic feet, or 12.3 cubic yards; about 13.6 yards with a 10% settling allowance.
How much soil do I need for a 4×8 raised bed?
A 4 ft × 8 ft bed filled 12 in deep holds 32 cubic feet, or 1.19 cubic yards. With 10% for settling that's 35.2 cubic feet: about 47 bags of 0.75 cu ft or 36 bags of 1 cu ft. Use a garden soil or raised-bed blend, not plain fill dirt.
What is the difference between topsoil, garden soil and fill dirt?
Topsoil is the upper layer of native soil, screened to remove rocks and roots; it's the base for lawns and grading. Garden soil is topsoil blended with compost or other organic matter for beds and raised beds. Fill dirt is subsoil with little organic matter, used to fill holes and raise grades; cap it with topsoil before planting.
Can a pickup truck carry a yard of topsoil?
Weight is the limit, not bed space. A cubic yard of dry topsoil weighs about a ton, which is at or above the payload of many half-ton pickups, and wet soil weighs more. Check the payload rating on your door sticker; this calculator plans about 1 ton per pickup load.