Whether you are levelling a lawn, building a planting bed or filling a raised garden, topsoil is sold in bulk by the cubic yard or in bags by the cubic foot. This topsoil calculator converts your measurements into both, estimates the weight so you know whether a pickup truck can haul it, and includes an allowance for settling.
How deep should topsoil be? For lawns on eroded or poor ground, Clemson University's lawn establishment guide suggests adding up to 3 inches of topsoil and tilling it in, which is the default here. Vegetable beds and raised beds are usually filled 6–12 inches deep. When the soil is down, cover beds with mulch — the mulch calculator sizes that — or check bulk volumes with the cubic yard calculator.
How to use the topsoil calculator
- Enter the length and width of the area, or choose Circle for round beds.
- Enter the depth of topsoil to add. For a raised bed, use the inside depth of the frame.
- Keep a 10–20% allowance; loose topsoil settles noticeably after watering and rolling. The default is 15%.
- Adjust density if your supplier lists it. Dry screened topsoil is lighter; wet soil is heavier.
- Enter prices per yard, ton or bag to compare bulk delivery with bagged soil.
Formula
Worked example
You are topdressing a 30 × 20 ft lawn area with 3 inches of topsoil.
- Area: 30 × 20 = 600 ft².
- Volume: 600 × 0.25 ft = 150 ft³ = 5.56 yd³.
- With 15% for settling: 5.56 × 1.15 = 6.39 yd³.
- Weight: 6.39 × 1.2 ≈ 7.7 tons — a delivery job, not a pickup run.
- In 0.75 ft³ bags it would be 230 bags, which shows why bulk is the norm for lawns.
Raised bed soil quick reference
| Bed size | Depth | Soil needed |
|---|---|---|
| 4 × 4 ft | 12 in | 16 ft³ (0.59 yd³) |
| 4 × 8 ft | 12 in | 32 ft³ (1.19 yd³) |
| 4 × 8 ft | 18 in | 48 ft³ (1.78 yd³) |
| 3 × 6 ft | 10 in | 15 ft³ (0.56 yd³) |
Figures before settling allowance.
Caveats and assumptions
- Topsoil weight varies widely with moisture and organic content; roughly 1 to 1.4 tons per cubic yard is common. Ask your supplier if weight matters for hauling.
- Bagged products labelled “garden soil” or “raised bed mix” may be lighter blends with compost; volume, not weight, is what matters for filling space.
- Adding soil over existing lawn more than an inch or two at a time can smother the grass; deeper fills usually mean reseeding or sodding.
- Do not pile soil against house siding or over tree roots; keep grade sloping away from foundations.
Frequently asked questions
How much does a yard of topsoil weigh?
Typically about 1 to 1.4 tons (2,000–2,800 lb), depending on moisture and composition. This calculator uses 1.2 tons by default.
How many bags of topsoil make a yard?
27 cubic feet make a yard, so 36 bags of 0.75 ft³, 27 bags of 1 ft³ or 18 bags of 1.5 ft³.
How much topsoil do I need for a new lawn?
If the existing soil is poor or eroded, Clemson Extension suggests adding up to 3 inches and tilling it in. At 3 inches, each 1,000 ft² needs about 9.3 yd³ before settling.
How much soil do I need for a 4×8 raised bed?
A 4 × 8 ft bed filled 12 inches deep holds 32 cubic feet, about 1.2 cubic yards. Add 10–20% for settling.
What is the difference between topsoil and fill dirt?
Topsoil is the upper, organic-rich layer suited to growing plants. Fill dirt is subsoil used to raise grade and is usually covered with topsoil.
Sources
- Clemson Cooperative Extension — Lawn Establishment — soil preparation and topsoil depth for lawns
- NIST — Unit Conversion
This calculator gives estimates for planning and education. Check measurements, local codes, supplier specs and your school's official policy before relying on a result. See our disclaimer and how we build and check calculators.