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′32.001.193216
3′ x 6′ x 0.75′13.500.50147
2′ x 4′ x 10″6.670.2574
5′ x 10′ x 1.5′75.002.787538
6′ x 3′ x 1′18.000.67189
8′ x 4′ x 18″48.001.784824
10′ x 2′ x 8″13.330.49147

  1. 4′ x 8′ x 1′:
    • Volume: 4 x 8 x 1 = 32 cu. ft.
    • Cubic yards: 32 ÷ 27 = 1.19 cu. yd.
  2. 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.
  3. 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.
  4. 5′ x 10′ x 1.5′:
    • Volume: 5 x 10 x 1.5 = 75 cu. ft.
    • Cubic yards: 75 ÷ 27 = 2.78 cu. yd.
  5. 6′ x 3′ x 1′:
    • Volume: 6 x 3 x 1 = 18 cu. ft.
    • Cubic yards: 18 ÷ 27 = 0.67 cu. yd.
  6. 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.
  7. 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:

  1. Measure the length, width, and depth of your raised bed in feet
  2. 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.

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