How to use it
- Enter the bed or lawn measurements.
- Enter the soil depth you plan to add.
- Choose bulk (cubic yards or m³) or bags. For bags, use the size printed on the bag.
- Adjust the waste allowance if your soil will settle or the ground is uneven.
Formula and assumptions
- Volume = area × depth
- Volume with waste = volume × (1 + waste % ÷ 100)
- Bags = round up (volume with waste ÷ volume of one bag)
- Bags sold by weight: bag volume = bag weight ÷ density
Order amounts always round up, never down. Prices apply to the rounded amount, in the unit your supplier sells by. See the methodology for constants and indicative densities.
Example
An 8 ft × 12 ft raised bed filled 6 in deep with 10% waste, in 0.75 cu ft bags:
- Before waste: 1.78 cu yd (1.36 m³)
- With waste: 1.96 cu yd (1.5 m³)
- Suggested order: 71 bags
Questions
How many bags of topsoil make a cubic yard?
A cubic yard is 27 cubic feet. That's 36 bags of 0.75 cu ft, 27 bags of 1 cu ft, or 18 bags of 1.5 cu ft, before any waste allowance.
Should I buy bulk or bagged topsoil?
Small beds are often easier with bags. Bigger jobs are usually cheaper in bulk. Enter your supplier prices for both options to compare.
Why does the calculator ask for density for some bags?
Some bags list a weight, like 40 lb, instead of a volume. Turning weight into volume needs the soil's density, so the calculator asks for it instead of guessing.
Does topsoil settle?
Loose soil often settles after watering and compaction. Many people add a little extra. You can include that in the waste allowance.