How to use the topsoil calculator
- Choose the shape of the area, or enter the area directly for irregular spaces.
- Enter the depth of topsoil you want to add.
- Leave the weight at the default (2,300 lb per yd³) or use your supplier’s figure.
- Pick a bag size if you are buying bags, or enter a bulk price.
Topsoil formula
Volume (ft³) = Area (ft²) × Depth (in) ÷ 12 Cubic yards = Cubic feet ÷ 27 Tons = Cubic yards × 1.15 (≈ 2,300 lb per yd³) Bags = Cubic feet ÷ bag size (cu ft)
Worked example
A new 20 × 10 ft lawn area with 4 in of topsoil:
- Volume = 200 × 4 ÷ 12 = 66.7 ft³ = 2.47 yd³
- Weight ≈ 2.47 × 1.15 = 2.84 US tons
- In 0.75 cu ft bags: 66.7 ÷ 0.75 = 89 bags — bulk is far easier
Topsoil coverage chart
| Depth | 1 yd³ covers | 1 m³ covers |
|---|---|---|
| 1 in (2.5 cm) | 324 ft² | 40 m² |
| 2 in (5 cm) | 162 ft² | 20 m² |
| 4 in (10 cm) | 81 ft² | 10 m² |
| 6 in (15 cm) | 54 ft² | 6.7 m² |
| 12 in (30 cm) | 27 ft² | 3.3 m² |
How deep should topsoil be?
| Project | Recommended depth |
|---|---|
| Top-dressing a lawn | ¼–½ in (6–12 mm) per application |
| New lawn from seed or sod | 4–6 in (10–15 cm) |
| Flower beds | 8–12 in (20–30 cm) |
| Vegetable gardens | 12 in (30 cm) or more |
| Trees and shrubs | Backfill the planting hole; 18–24 in deep zone |
Filling low spots and grading
For uneven ground, depths vary across the area. Split the yard into zones — for example a 10 × 20 ft dip that needs about 3 in, and the rest that needs 1 in — calculate each zone separately and add the volumes. When grading around a house, slope the soil away from the foundation by about 6 in over the first 10 ft (5%) so rainwater drains away. Compact fill in layers of 4–6 in and water it to help it settle before you seed or lay sod.
Bulk or bags?
Bags are handy for small beds and planters, but they cost several times more per cubic yard. Once you need more than about one cubic yard, bulk delivery is usually cheaper and much less work to spread — and you avoid a pile of plastic bags.
Buying good topsoil
- Ask for screened topsoil — it has stones, roots and clods removed.
- Look at it before delivery: it should be dark, crumbly and smell earthy, not sour.
- Avoid soil full of weeds or construction debris; cheap “fill dirt” is not topsoil.
- Mix in compost (about 25–30%) for vegetable beds — or use our Raised Bed Soil Calculator.
- Plan delivery access: a dump truck needs firm ground; put a tarp down to protect the driveway.