Soil Calculator
Enter the size of your bed or lawn area and the depth you want to fill. The calculator converts everything to cubic feet, cubic yards, cubic metres and bags, so you can buy bulk soil or bagged soil with confidence.
View formula
How to use the Soil Calculator
- Choose the shape of the area (rectangle or circle).
- Enter the length and width (or the diameter) and the depth you want to add.
- Pick the bag size you plan to buy, or ignore it if you are ordering bulk soil by the yard.
- Press Calculate: use Show the calculation to see every step.
How the soil calculator works
Soil is sold by volume, so the job is to turn the area you want to cover and the depth you want into a volume. Because depth is usually measured in inches while length and width are in feet, the depth is divided by 12 first so every measurement is in feet.
There are 27 cubic feet in one cubic yard (3 ft × 3 ft × 3 ft), which is the unit most landscape suppliers use for bulk deliveries. In metric, multiply length × width in metres by the depth in centimetres divided by 100 to get cubic metres.
Worked example
You are filling a 12 ft × 4 ft vegetable bed with 6 inches of new soil, using 1 cu ft bags.
- Area: 12 × 4 = 48 sq ft
- Volume: 48 × (6 ÷ 12) = 24 cu ft
- Cubic yards: 24 ÷ 27 = 0.89 cu yd
- Bags: 24 ÷ 1 = 24 bags
How deep should soil be?
| Project | Typical depth | Notes |
|---|---|---|
| Top-dressing a lawn | ¼ to ½ in (0.5 to 1 cm) | Thin layers so grass is not smothered |
| Leveling low spots | 1 to 2 in (2.5 to 5 cm) | Add in stages, letting grass grow through |
| New lawn from seed or sod | 4 to 6 in (10 to 15 cm) | Loosen the subsoil underneath first |
| Flower and shrub beds | 6 to 12 in (15 to 30 cm) | Deeper for shrubs and perennials |
| Vegetable beds | 8 to 12 in (20 to 30 cm) | Most vegetable roots live in the top foot |
Bulk or bagged?
Bagged soil is convenient for small jobs and easy to move. Once you need more than roughly one to two cubic yards (27 to 54 cu ft), bulk delivery is usually cheaper per yard, but check minimum orders and delivery fees with local suppliers. Remember that soil settles after watering, so many gardeners add 10 to 20% extra when filling beds to the brim.
FAQ
Soil Calculator: frequently asked questions
How many bags of soil make a cubic yard?
One cubic yard is 27 cubic feet, so it takes 27 one-cubic-foot bags, 36 bags of 0.75 cu ft, 18 bags of 1.5 cu ft or 13.5 bags of 2 cu ft.
How much does a cubic yard of soil cover?
One cubic yard covers about 324 sq ft at 1 inch deep, 162 sq ft at 2 inches, 81 sq ft at 4 inches and 54 sq ft at 6 inches.
Should I order extra soil?
Yes, loose soil settles once it is watered and walked on. Adding 10 to 20% is common for beds you fill to the top; for top-dressing a lawn the exact amount is usually fine.
Can I use this for a round bed or tree ring?
Yes. Choose “Circle” and enter the diameter. The calculator uses π × radius² to find the area before multiplying by depth.
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