How to use the topsoil calculator
- Choose what you're filling. Use a rectangle, circle or known area for lawns and in-ground beds, or Raised bed to enter the inside length, width and soil depth of a box.
- Set the depth. It depends on the job — see the table below. For leveling a sloped or uneven area, use the average depth: measure at several points and average them.
- Keep a settling allowance. Delivered topsoil is loose and fluffy. Rain, watering and foot traffic firm it up, so the layer ends up thinner than it was spread.
- Check the soil weight if you're buying by the ton. The default of 1.1 tons per cubic yard is a typical figure for dry, loose topsoil. Wet soil is much heavier, so ask your supplier what they use.
The topsoil formula
Cubic yards = cubic feet ÷ 27
Bags = cubic feet ÷ bag size (cu ft), rounded up
Tons = cubic yards × tons per cubic yard
For a raised bed, the area is the inside length × width and the depth is how deep you'll fill it, then multiply by the number of beds.
Worked example: a new 1,000 sq ft lawn
A 25 × 40 ft lawn area is 1,000 sq ft. At 4 in of topsoil: 1,000 × 4 ÷ 12 = 333.3 cubic feet. Adding 10% for settling gives 366.7 cubic feet, or 366.7 ÷ 27 = 13.58 cubic yards. At 1.1 tons per yard that weighs about 14.9 tons. In 1 cu ft bags it would take 367 bags — a clear case for bulk delivery.
Worked example: a 4 × 8 ft raised bed
Filled 12 in deep, a 4 × 8 bed holds 4 × 8 × 1 = 32 cubic feet. With 10% for settling that's 35.2 cubic feet, or 1.30 cubic yards — 36 bags of 1 cu ft.
How deep should topsoil be?
| Project | Typical depth |
|---|---|
| Top dressing an existing lawn | ¼–½ in at a time, so grass can grow through |
| New lawn from seed or sod | 4–6 in |
| Flower beds | 6–8 in |
| In-ground vegetable garden | 8–12 in |
| Raised beds | The full bed depth, commonly 6–12 in or more for root crops |
To fill a deep low spot in a lawn, add soil in thin layers over several weeks rather than burying the grass in one go. Laying sod on the new soil? The sod calculator works out the pallets.
Bag sizes and weights
| Unit | Volume | Per cubic yard |
|---|---|---|
| 0.75 cu ft bag | 0.75 cu ft | 36 bags |
| 1 cu ft bag | 1 cu ft | 27 bags |
| 40 L bag | 1.41 cu ft | 19.1 bags |
| 50 L bag | 1.77 cu ft | 15.3 bags |
| Bulk, dry and loose | 1 cu yd | About 1–1.2 tons |
Some bags are marketed by weight, such as 40 lb, but most also print a volume on the label — a 40 lb bag of topsoil is commonly labelled 0.75 cu ft. Always count bags by the volume on the label (choose Other size if it isn't listed above), not by weight: bagged soil is often moist, so its weight says little about how much space it fills. Bagged products vary, so check the label.
Weight matters if you're hauling it yourself: even dry, a cubic yard of topsoil weighs around a ton, which is close to or beyond the payload of many half-ton pickups. Check the payload rating on the door-jamb sticker before loading up.
Screened vs. unscreened topsoil
- Screened topsoil has been passed through a mesh to remove rocks, roots and clumps. It spreads evenly and is the one to use for lawns, beds and top dressing.
- Unscreened topsoil is cheaper but lumpy. It's fine for rough grading or filling the bottom of a deep area that you'll cap with screened soil.
- Fill dirt is mostly subsoil with little organic matter. It's for raising grade, not for growing.
- Garden or raised-bed mix is topsoil blended with compost. Many gardeners prefer it for raised beds because straight topsoil can pack down hard in a box. The volume you need is the same.
Test before you buy
A soil test — available through most state cooperative extension services — tells you the pH and nutrient levels of your existing soil, so you know whether you need new topsoil or just amendments. When buying in bulk, ask the supplier where the soil comes from and whether they can share a recent analysis, and look at a sample: it should be dark, crumbly and free of trash, large stones and weed roots.
Finishing the beds once they're planted? The mulch calculator covers the top layer.
Frequently asked questions
How many bags of topsoil are in a cubic yard?
A cubic yard is 27 cubic feet, so it equals 27 bags of 1 cu ft or 36 bags of 0.75 cu ft. Beyond a yard or two, bulk delivery is usually cheaper and far less work.
How much does a cubic yard of topsoil weigh?
Dry, loose topsoil typically weighs about 1–1.2 tons (2,000–2,400 lb) per cubic yard. Wet soil can weigh roughly 1.5 tons or more, so the weight on a delivery ticket varies with the weather.
How much topsoil do I need for a new lawn?
Plan on 4–6 inches. For 1,000 sq ft at 4 inches, that's 12.3 cubic yards, or about 13.6 cubic yards with 10% for settling.
How much soil does a 4 × 8 raised bed need?
Filled 12 inches deep, a 4 × 8 ft bed holds 32 cubic feet (1.19 cubic yards). Allowing 10% for settling, buy about 35 cubic feet — 36 bags of 1 cu ft or 1.3 cubic yards in bulk.
Does topsoil settle?
Yes. Freshly delivered soil is loose and compacts as it is watered and walked on. Adding 10–20% is a common allowance for new lawns and beds; for a thin top dressing you can skip it.