How the calculation works
Soil is sold by the cubic yard (or cubic metre) in bulk, and by the bag at garden centres. The calculator finds the volume of your area, adds settling for soil that sinks after it is spread and watered, adds overage, and converts to weight.
Worked example
A 40 × 25 ft lawn is 1,000 ft². At 4 inches deep that is 333 ft³, or 12.3 cubic yards. Add 10% for settling (13.6 yards) and 10% for uneven ground, and you should order about 15 yards. At 1.1 tons per yard, that is about 16.4 tons.
How deep should topsoil be?
| Project | Depth | Usual soil |
|---|---|---|
| New lawn | 4–6 in · 10–15 cm | Screened topsoil |
| Top-dress a lawn | ¼–½ in · 0.5–1 cm | Compost |
| New garden bed | 6–12 in · 15–30 cm | Garden soil (topsoil and compost blend) |
| Raised bed | Height of the box · 12 in is common | Raised bed mix |
| Fill low spots | 1–3 in at a time · 2.5–7.5 cm | Screened topsoil |
| Raise the grade | Compact in 4–6 in layers · 10–15 cm | Fill dirt |
For a new lawn, loosen the ground underneath before spreading so the new soil and the old one blend rather than forming a layer.
Why add settling?
Soil arrives loose and fluffy from the screener. Once it is raked, rolled and watered it sinks, and the depth you measured shrinks with it. The calculator adds 10% for topsoil and garden soil, 15% for raised bed mix, and 20% for fill dirt, which you compact on purpose. Compost is spread thin, so we leave it at the measured volume.
Soil types and weights
These are typical figures for fairly dry material. Moisture changes the weight a lot, so use them for planning rather than load limits.
| Material | Tons / yd³ | Tonnes / m³ | Settling added | Bag size |
|---|---|---|---|---|
| Screened topsoil | 1.10 | 1.31 | +10% | 0.75 cu ft |
| Garden soil (topsoil and compost blend) | 1.00 | 1.19 | +10% | 1 cu ft |
| Compost | 0.55 | 0.65 | None | 1 cu ft |
| Raised bed mix | 0.80 | 0.95 | +15% | 1.5 cu ft |
| Fill dirt | 1.20 | 1.42 | +20% | 0.75 cu ft |
Raised beds
Enter one bed's length, width and height, then put the number of beds in "How many". A 4 × 8 ft bed 12 inches deep holds 1.2 cubic yards, so three of them need about 3.6 yards before settling. Many gardeners fill the bottom of very deep beds with cheaper fill and use good mix for the top 8 to 12 inches.
Bags or bulk?
Bagged topsoil is usually 0.75 cu ft (about 40 lb), so it takes 36 bags to make a yard. Bags work for patching and small beds. Beyond half a yard or so, bulk delivery saves money and a lot of lifting. A yard of topsoil weighs about a ton, so a half-ton pickup can carry about one yard at a time.
Common questions
How much topsoil do I need for a new lawn?
Plan on 4 to 6 inches. For 1,000 square feet at 4 inches, that is 12.3 cubic yards before settling, or about 15 yards once you add 10% for settling and 10% for uneven ground.
How much does a yard of topsoil weigh?
About 1 to 1.1 tons (2,000 to 2,200 lb) when it is fairly dry. Wet soil weighs more, so a load delivered after rain can be noticeably heavier.
How many bags of topsoil make a yard?
Thirty-six bags of 0.75 cu ft, or 27 bags of 1 cu ft. Past about half a yard, bulk delivery is usually simpler.
How much soil do I need for a raised bed?
Multiply length × width × height in feet and divide by 27. A 4 × 8 ft bed 12 inches deep holds 32 cubic feet, or 1.2 cubic yards. New beds settle, so we add 15% for raised bed mix. Use the "How many" box if you are filling several beds the same size.
What is the difference between topsoil, garden soil and fill dirt?
Topsoil is the screened upper layer of soil, used under lawns and for levelling. Garden soil is topsoil blended with compost for planting. Fill dirt is subsoil with little organic matter, used to raise the grade or fill holes, and it should be compacted.
Sources: typical soil weights from North American landscape supplier price sheets. More on how we calculate.