Use this raised bed soil calculator to determine the precise amount of soil needed for their raised garden beds.
How Deep Should Raised Bed Soil Be?
- 6-8 inches: Suitable for shallow-rooted plants like lettuce, herbs, and some flowers
- 10-12 inches: Ideal for most vegetables, including tomatoes, peppers, and beans
- 18-24 inches: Necessary for deep-rooted vegetables like carrots and parsnips
For most general gardening purposes, a depth of 10-12 inches is recommended. This depth provides ample room for root growth while balancing soil volume and cost considerations.
Raised Bed Soil Calculator
| Bed Size (L x W x D) | Volume (cu. ft.) | Volume (cu. yd.) | Bags Needed (1 cu. ft.) | Bags Needed (2 cu. ft.) |
|---|---|---|---|---|
| 4′ x 8′ x 1′ | 32.00 | 1.19 | 32 | 16 |
| 3′ x 6′ x 0.75′ | 13.50 | 0.50 | 14 | 7 |
| 2′ x 4′ x 10″ | 6.67 | 0.25 | 7 | 4 |
| 5′ x 10′ x 1.5′ | 75.00 | 2.78 | 75 | 38 |
| 6′ x 3′ x 1′ | 18.00 | 0.67 | 18 | 9 |
| 8′ x 4′ x 18″ | 48.00 | 1.78 | 48 | 24 |
| 10′ x 2′ x 8″ | 13.33 | 0.49 | 14 | 7 |
- 4′ x 8′ x 1′:
- Volume: 4 x 8 x 1 = 32 cu. ft.
- Cubic yards: 32 ÷ 27 = 1.19 cu. yd.
- 3′ x 6′ x 0.75′:
- Volume: 3 x 6 x 0.75 = 13.5 cu. ft.
- Cubic yards: 13.5 ÷ 27 = 0.5 cu. yd.
- 2′ x 4′ x 10″:
- Convert 10″ to feet: 10 ÷ 12 = 0.833′
- Volume: 2 x 4 x 0.833 = 6.67 cu. ft.
- Cubic yards: 6.67 ÷ 27 = 0.25 cu. yd.
- 5′ x 10′ x 1.5′:
- Volume: 5 x 10 x 1.5 = 75 cu. ft.
- Cubic yards: 75 ÷ 27 = 2.78 cu. yd.
- 6′ x 3′ x 1′:
- Volume: 6 x 3 x 1 = 18 cu. ft.
- Cubic yards: 18 ÷ 27 = 0.67 cu. yd.
- 8′ x 4′ x 18″:
- Convert 18″ to feet: 18 ÷ 12 = 1.5′
- Volume: 8 x 4 x 1.5 = 48 cu. ft.
- Cubic yards: 48 ÷ 27 = 1.78 cu. yd.
- 10′ x 2′ x 8″:
- Convert 8″ to feet: 8 ÷ 12 = 0.667′
- Volume: 10 x 2 x 0.667 = 13.33 cu. ft.
- Cubic yards: 13.33 ÷ 27 = 0.49 cu. yd.
Raised Bed Soil Calculation Formula
The formula for calculating the amount of soil needed for a raised bed is simple, usually cubic feet or cubic yards).
The basic formula is:
Volume = Length x Width x Depth
To calculate the volume in cubic feet:
- Measure the length, width, and depth of your raised bed in feet
- Multiply these three measurements together
For example, if your raised bed is 8 feet long, 4 feet wide, and 1 foot deep: Volume = 8 x 4 x 1 = 32 cubic feet
To convert cubic feet to cubic yards (a common unit for bulk soil orders), divide the result by 27: Cubic Yards = Cubic Feet ÷ 27
In our example: 32 ÷ 27 = 1.19 cubic yards
How Much Soil for a 4×8 Raised Bed?
A 4×8 raised bed is a popular size for many gardeners.
Assuming a depth of 1 foot (which is suitable for most plants): Volume = 4 x 8 x 1 = 32 cubic feet
This means you would need 32 cubic feet of soil to fill a 4×8 raised bed with a depth of 1 foot.
If you prefer to order in cubic yards: 32 ÷ 27 = 1.19 cubic yards
You would need approximately 1.2 cubic yards of soil for a 4×8 raised bed with a 1-foot depth.
How Many Bags of Soil Do I Need for a 2×4 Raised Bed?
Assuming a depth of 10 inches (0.83 feet): Volume = 2 x 4 x 0.83 = 6.64 cubic feet
Most bagged soils are sold in cubic feet. Common bag sizes include:
- 0.75 cubic feet
- 1 cubic foot
- 1.5 cubic feet
- 2 cubic feet
To calculate the number of bags needed, divide the total volume by the bag size:
- For 1 cubic foot bags: 6.64 ÷ 1 = 6.64 bags (round up to 7 bags)
- For 1.5 cubic foot bags: 6.64 ÷ 1.5 = 4.43 bags (round up to 5 bags)
- For 2 cubic foot bags: 6.64 ÷ 2 = 3.32 bags (round up to 4 bags)
Always round up to ensure you have enough soil to fill your raised bed completely.
