Raised bed soil calculator
Soil in cubic feet = length (feet) × width (feet) × depth (inches) ÷ 12. A 4×8 raised bed 12 inches deep needs 32 cubic feet of soil: 16 bags of 2 cubic feet, or about 1.2 cubic yards. Divide cubic feet by 27 for cubic yards.
| Bed (feet) | 6 in deep | 8 in deep | 12 in deep | 18 in deep |
|---|---|---|---|---|
| 2×4 | 4 | 5.3 | 8 | 12 |
| 2×6 | 6 | 8 | 12 | 18 |
| 2×8 | 8 | 10.7 | 16 | 24 |
| 3×3 | 4.5 | 6 | 9 | 13.5 |
| 3×6 | 9 | 12 | 18 | 27 |
| 4×4 | 8 | 10.7 | 16 | 24 |
| 4×6 | 12 | 16 | 24 | 36 |
| 4×8 | 16 | 21.3 | 32 | 48 |
| 4×12 | 24 | 32 | 48 | 72 |
| 8×8 | 32 | 42.7 | 64 | 96 |
Fill it with a 1:1 mix of compost and garden soil or topsoil (University of Illinois Extension). Ken Johnson, University of Illinois Extension, “Raised Bed Gardening” (July 2023), which works the same sum: a 6 × 3 foot bed with 12-inch sides holds 18 cubic feet.
Updated