How to calculate a lawn topsoil
A new lawn starts with a layer of good soil, and large yards need a delivery truck rather than bags.
- Find the lawn area by multiplying length by width, or use the irregular area calculator.
- Pick a depth, commonly 4 to 6 inches for a new lawn.
- Order 10 percent extra for settling.
- Rake level and roll lightly before seeding or laying sod.
Worked example
For a typical lawn topsoil with length 40 ft, width 25 ft, depth 4 in, the volume is 333.33 cubic feet. Divide by 27 for 12.35 cubic yards. With a 10 percent allowance, plan for 13.58 cubic yards.
In topsoil, 12.35 cubic yards weighs about 13.58 US tons at a planning value of 2,200 pounds per cubic yard.
Lawn Topsoil sizes and quantities
These common sizes are calculated with the same formula as the tool above, so you can find your number quickly.
| Size | Cubic feet | Cubic yards | With 10 percent extra | US tons |
|---|---|---|---|---|
| 20 by 20 ft, 4 in | 133.33 | 4.94 | 5.43 | 5.43 |
| 40 by 25 ft, 4 in | 333.33 | 12.35 | 13.58 | 13.58 |
| 60 by 50 ft, 4 in | 1,000.00 | 37.04 | 40.74 | 40.74 |
| 100 by 80 ft, 6 in | 4,000.00 | 148.15 | 162.96 | 162.96 |
Tips
- Test the existing soil before buying more.
- Screened topsoil spreads more evenly.
- Spread soil in dry weather to avoid compacting it.
Common mistakes to avoid
- Spreading too deep over existing grass.
- Not matching the finished grade to patios and walks.
- Ignoring drainage.
These figures are planning estimates. Real material varies in moisture, size, and compaction, so confirm weights and order quantities with your supplier.
Frequently asked questions
How many cubic yards do I need for a lawn topsoil?
Multiply the dimensions in feet and divide by 27. The example above, length 40 ft, width 25 ft, depth 4 in, needs 12.35 cubic yards before waste.
How much extra should I order?
Add 5 to 10 percent for waste. Add more if the ground is uneven or the material is loose.
Can I enter inches and feet together?
Yes. Each box has its own unit selector, so you can mix feet and inches.
How much does lawn topsoil material weigh?
12.35 cubic yards of topsoil weighs about 13.58 US tons as a planning value.