How Much Topsoil Do I Need? Raised Beds, New Lawns and Leveling
Calculate topsoil for raised beds, new lawns and low spots, plan for settling, and choose between topsoil, garden mix and fill dirt.
Soil is the most common thing people order by the cubic yard, and the most likely to come up short. Unlike mulch, which sits on top of the ground, soil is used to fill: raised beds, low spots, new lawn areas and planting holes. Fill settles, sometimes a lot, so the calculation needs one more step than a mulch estimate.
Three common soil jobs
1. Filling raised beds
Multiply the inside length, width and height of the bed in feet. A bed 8 ft × 4 ft × 1 ft holds 32 cubic feet, or 1.19 cubic yards. Many gardeners fill the bottom third of very tall beds with logs or branches to save soil (a method sometimes called hügelkultur); subtract that volume if you do.
2. Topdressing or starting a lawn
New lawns from seed or sod do best with 4–6 inches of good soil. A 30 × 40 ft area (1,200 sq ft) at 4 inches needs 1,200 × 4 ÷ 324 = 14.8 cubic yards. For topdressing an existing lawn, a quarter to half an inch is plenty; the same area needs under 2 yards.
3. Leveling low spots
Measure the depth of the hollow at several points and average them, then multiply by the area. A dip 10 ft across that averages 3 inches deep is roughly a 10 ft circle: 78.5 sq ft × 0.25 ft = 19.6 cubic feet, or 0.73 yards. Deep fills should be added in layers of a few inches and firmed between layers.
Plan for settling
Freshly delivered soil is fluffy. Once it is watered, walked on and rained on, it consolidates. How much depends on the soil and how it was handled, but many landscapers plan on 10–20% settling for screened topsoil and garden mixes. In practice:
- Add 15–20% to your calculated volume for raised beds and low spots.
- Fill raised beds slightly above the rim; they will drop over the first few weeks.
- Keep a small pile or a few bags aside for topping up after the first heavy rain.
Our cubic yard calculator has an "extra" field for exactly this; enter 15 or 20.
Topsoil, garden mix or fill dirt?
| Product | What it is | Best for |
|---|---|---|
| Fill dirt | Subsoil with little organic matter, often clay or sand | Raising grade, filling holes, under patios |
| Screened topsoil | Upper soil layer with rocks and debris removed | Lawns, general landscaping, leveling |
| Garden or raised-bed mix | Topsoil blended with compost or other organic matter | Vegetable beds, flower beds, containers |
| Compost | Decomposed organic material | Mixing into existing soil, topdressing |
A cost-saving approach for deep areas is to use fill dirt for the lower layer and a better soil only in the top 6–12 inches where roots grow. Fill dirt is not suitable directly under plants or lawn.
Checking soil quality
Ask the supplier where the soil came from and whether it has been screened and tested. Good topsoil crumbles in your hand, smells earthy and has no construction debris. If you are growing vegetables, a soil test from your state's cooperative extension service tells you the pH and nutrient levels so you can amend the soil properly.
Worked example: a vegetable garden
You are building four raised beds, each 10 ft × 4 ft × 16 inches. Each bed holds 10 × 4 × (16 ÷ 12) = 53.3 cubic feet. Four beds hold 213.3 cubic feet, or 7.9 yards. Adding 15% for settling gives 9.1 yards. Ordering 9 yards of raised-bed mix and topping up from a few bags later is a sensible plan. Note that 9 yards of soil weighs roughly 9–12 tons, a full dump-truck load, so delivery is the only practical option; see what a cubic yard weighs.
Related tools
- Laying a gravel base or path next to the beds? Use the gravel calculator.
- Need the area of an irregular lawn first? See how to measure irregular areas.
Further reading from official sources
- Unit conversion: SI and U.S. customary units – National Institute of Standards and Technology (NIST)
