Landscaping
How to Estimate Topsoil for Your Lawn
Estimate how much topsoil you need for a new lawn, top-dressing or levelling. Recommended depths, worked examples, settling allowance and weight for transport.
Good topsoil is the foundation of a healthy lawn. Whether you are starting a lawn on bare subsoil, top-dressing an existing lawn or filling low spots, the calculation is the same: area × depth, plus an allowance for settling.
How deep should topsoil be?
| Project | Typical depth |
|---|---|
| New lawn from seed or sod | 4–6 in (10–15 cm) |
| Top-dressing an existing lawn | ¼–½ in (6–12 mm) |
| Filling low spots | Depth of the hollow |
| Vegetable or raised beds | 8–12 in (20–30 cm) |
Deeper topsoil holds more water and gives roots more room. If your existing soil is compacted subsoil, it is usually worth loosening it before adding topsoil.
Worked example
Example
New lawn: 40 × 30 ft at 5 in deep
- Area: 40 × 30 = 1,200 ft²
- Volume: 1,200 × (5 ÷ 12) = 500 ft³
- Cubic yards: 500 ÷ 27 = 18.5 yd³
- With 10% settling: 20.4 yd³
Result: Order about 20 cubic yards of topsoil.
In metric, 111 m² at 12.5 cm is 13.9 m³, or about 15.3 m³ with 10% extra.
Allowing for settling
Loose topsoil settles as it is raked, rolled and watered. How much depends on the soil's texture and moisture when delivered. Adding around 10–20% is a common way to reach the finished depth you want.
How much does topsoil weigh?
Dry, loose topsoil is often around 1–1.3 tons per cubic yard; wet soil can be considerably heavier. This matters if you are collecting soil yourself: many light trucks and small trailers can only carry a fraction of a cubic yard safely.
Check your vehicle and trailer payload ratings before loading topsoil. Overloading affects braking and steering.
Buying good topsoil
- Ask whether the soil has been screened to remove stones and roots.
- Look for a loam texture: not sticky like clay, not gritty like sand.
- Ask about organic matter content and whether it has been tested.
- Avoid soil with visible weeds or debris.
Once your topsoil is down, the grass seed calculator will tell you how much seed to buy.
Try the Topsoil Calculator
Topsoil volume, estimated weight and bag count for lawns and garden beds.
Frequently asked questions
How much area does a cubic yard of topsoil cover?
At 4 in deep, about 81 ft². At 6 in, about 54 ft². At ½ in for top-dressing, about 648 ft².
Is bagged topsoil worth it?
Bags suit small jobs like patching or containers. For a whole lawn, bulk delivery is usually far cheaper per cubic yard.
Can I put topsoil over grass?
Thin top-dressing (under ½ in) can go over existing grass. Deeper layers will smother it, so remove or kill the old turf first.
About the author
Written by the BuildCalcWorld Editorial Team. Our guides explain standard estimating methods with worked examples you can verify. Material properties vary by product and region, so always confirm specifications with your supplier. Published . Learn more about us.
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