Soil Calculator
Find out how much soil your raised bed or container needs — in cubic feet, cubic yards, and bags — before you buy.
How the Soil Formula Works
Soil volume is length × width × depth, with all three in the same unit. Using feet gives you cubic feet, which is how bagged soil is labeled. Bulk soil is sold by the cubic yard, and one cubic yard is 27 cubic feet (3 ft × 3 ft × 3 ft), so divide cubic feet by 27.
Worked example: a 4 × 8 ft bed filled 12 inches deep is 8 × 4 × 1 = 32 cubic feet, or 32 ÷ 27 ≈ 1.19 cubic yards. In 1.5 cu ft bags that is 32 ÷ 1.5 = 21.3, so 22 bags.
- Measure the inside of the frame, and the depth you actually plan to fill — not the board height.
- Bulk suppliers often sell in quarter- or half-yard steps, so round your yard figure up to what they offer.
- For very deep beds, some gardeners fill the bottom with cheaper coarse material and calculate quality mix for only the top 12–15 inches.
For the full walkthrough, including multiple beds and settling, read How Much Soil You Need for a Raised Bed.