Topsoil Calculator
Plan topsoil for a new lawn, a garden bed or filling low spots. Enter the area and depth to get cubic yards (how bulk soil is sold), tons (for hauling) and the number of 40 lb bags.
How to use the topsoil calculator
- Enter the size of the area. Add separate areas for beds of different shapes with Add another area.
- Set the depth of new soil you want after spreading: 4–6 in for a new lawn, 6–12 in for new planting beds, ¼–½ in for top-dressing an existing lawn.
- Keep the density at about 1.1 tons per cubic yard unless your supplier gives you a figure; it only affects the weight.
- Add a settling allowance if the finished depth matters, because loose soil settles after rain and watering.
- Compare bulk and bagged prices under Cost estimate.
The topsoil formula
Topsoil is sold by the cubic yard in bulk and by the bag (usually 40 lb, about 0.75 ft³) at garden centers.
- Volume (ft³) = area (ft²) × depth (in) ÷ 12 × (1 + waste) × (1 + settling)
- Cubic yards = cubic feet ÷ 27
- Tons = cubic yards × density
- Bags = cubic feet ÷ 0.75, rounded up
Weight depends heavily on moisture. Hensons' lists soil at about 2,200 lb per cubic yard; Topsoil.com gives about 2,000 lb dry, 2,200–2,600 lb moist and up to 3,000 lb saturated. The calculator uses 1.1 tons (2,200 lb) as a middle value.
Worked example: 1,000 ft² at 4 in
This is the lawn area loaded above: 40 × 25 ft.
- Volume: 1,000 × 4 ÷ 12 = 333.3 ft³ (12.35 yd³).
- Add 10%: 366.67 ft³, which is 13.58 yd³.
- Weight: 13.58 × 1.1 ≈ 14.94 tons: more than a pickup can carry in one trip, so plan on delivery.
- In 0.75 ft³ bags it would take 489 bags, which shows why bulk soil is the usual choice for anything bigger than a bed or two.
How deep should topsoil be?
For a new lawn, extension services describe preparing the top 4–6 in of soil (Purdue Extension); NC State notes that native topsoil is usually 4–8 in deep. Flower and vegetable beds are often given 6–12 in of garden soil (Hensons'). For top-dressing an existing lawn, use only ¼–½ in at a time so the grass can grow through. Raised beds are filled to the full height of the frame.
Topsoil needed per 100 ft² by depth
| Depth | Yd³ per 100 ft² | Tons per 100 ft² (1.1 t/yd³) | 0.75 ft³ bags per 100 ft² | Area 1 yd³ covers |
|---|---|---|---|---|
| 1 in | 0.31 | 0.34 | 12 | 324 ft² |
| 2 in | 0.62 | 0.68 | 23 | 162 ft² |
| 4 in | 1.23 | 1.36 | 45 | 81 ft² |
| 6 in | 1.85 | 2.04 | 67 | 54 ft² |
| 8 in | 2.47 | 2.72 | 89 | 41 ft² |
| 12 in | 3.7 | 4.07 | 134 | 27 ft² |
No waste or settling added. Topsoil weight varies with moisture; ask your supplier.
Tips for buying topsoil
- Ask for screened topsoil. Screening removes stones and roots, so it spreads evenly and you get more usable soil per yard.
- Order a little extra. Soil settles after the first heavy rain. If the finished level matters (around a patio or path), add a settling allowance or plan a light top-up later.
- Check where it comes from. NC State Extension warns that topsoil brought in from other sites can carry weeds and plant diseases; buy from a supplier who screens and can tell you the source.
- Mix it in. Rake new topsoil into the top couple of inches of the existing ground instead of leaving a distinct layer, so water and roots move through it.
Frequently asked questions
How much topsoil do I need for 1,000 square feet?
At 4 in deep, 1,000 ft² needs 333 ft³, which is 12.35 cubic yards before waste. At 6 in it is 18.5 cubic yards, and at 2 in it is about 6.2 cubic yards.
How much does a yard of topsoil weigh?
Roughly 1 to 1.3 tons (2,000–2,600 lb) per cubic yard depending on moisture, and up to about 1.5 tons when saturated. Dry topsoil is at the low end.
How many bags of topsoil make a yard?
A typical 40 lb bag holds about 0.75 ft³, so one cubic yard (27 ft³) is 36 bags.
How deep should topsoil be for a new lawn?
Aim for 4–6 in of good soil for grass roots, as extension guides on establishing turf describe. Top-dressing an existing lawn uses much less: ¼–½ in at a time.
Is topsoil sold by the yard or by the ton?
Most landscape suppliers sell bulk topsoil by the cubic yard; some sell by the ton. The calculator shows both. Garden centers sell bags by volume (cubic feet) or by weight.