Raised bed soil calculator: how much soil do I need for a raised garden bed?
22 bags
1.19 cubic yards · 32 cubic feet · for 8 × 4 ft at 12 in
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Enter it the way you measured it: 4.5, 4 1/2,
3/8 or 10' 6".
22 bags
1.19 cubic yards · 32 cubic feet
A 4 by 8 ft raised garden bed filled 12 inches deep takes 32 cubic feet of soil, which is 1.19 cubic yards in bulk or 22 bags of the 1.5 cubic foot size.
A worked example
Three beds of 6 1/2 by 3 ft filled 10 inches deep, in 2 cu ft bags, needs 25 bags of 2 cu ft, or 1.81 cubic yards. Each bed is 6.5 × 3 ft × 10 in, 16.25 cubic feet, so the three hold 48.75 cubic feet. At 2 cubic feet a bag that is 24.4 bags, rounded up to 25; in bulk it is 48.75 ÷ 27 = 1.81 cubic yards.
How do I work out soil for several raised beds?
For beds of the same size, enter one bed and the number of beds: three 4 by 8 ft beds at 12 inches are 96 cubic feet, 3.56 cubic yards. For beds of different sizes, run each one and add the cubic feet. A round bed is 3.14 × radius × radius × depth; a 4 ft round bed 12 inches deep holds 12.6 cubic feet.
How many bags of soil are in a cubic yard?
A cubic yard is 27 cubic feet, so it is 27 bags of 1 cubic foot, 18 bags of 1.5, 13.5 bags of 2 and 9 bags of 3. Comparing the bag price times that count with the delivered price of a cubic yard shows which is cheaper for your beds.
What else it is called
Raised bed soil is sold as raised bed mix, garden soil, or as topsoil and compost blended on site. Whatever the mix, the volume to fill the bed is the same geometry; in bulk it is sold by the cubic yard and in bags by the cubic foot. For compost alone there is a separate compost calculator.
Common sizes
| Area | 6 in deep | 8 in deep | 10 in deep | 12 in deep | 18 in deep |
|---|---|---|---|---|---|
| 2 × 4 ft | 0.15 | 0.20 | 0.25 | 0.30 | 0.45 |
| 2 × 8 ft | 0.30 | 0.40 | 0.50 | 0.60 | 0.89 |
| 3 × 6 ft | 0.34 | 0.45 | 0.56 | 0.67 | 1.00 |
| 4 × 4 ft | 0.30 | 0.40 | 0.50 | 0.60 | 0.89 |
| 4 × 8 ft | 0.60 | 0.80 | 0.99 | 1.19 | 1.78 |
| 4 × 12 ft | 0.89 | 1.19 | 1.49 | 1.78 | 2.67 |
| 4 × 16 ft | 1.19 | 1.59 | 1.98 | 2.38 | 3.56 |
Cubic yards, rounded up to two decimals. Round up again to what your supplier will deliver.
Where the numbers come from
- Volume is geometry: length × width × depth, in cubic feet, times the number of beds. 1 cubic yard = 27 cubic feet, exact by definition, so a 4 by 8 ft bed 12 inches deep, 32 cubic feet, is 1.19 cubic yards.
- Bags: the volume in cubic feet is printed on every bag of garden soil, and the count is the total divided by it, rounded up. The calculator takes the bag size you buy rather than assuming one.
Bag counts are rounded up. Bagged soil is loose and settles after watering, so a bed filled level with the top sits lower after the first few weeks; this count is the volume of the bed, not extra for settling.
By Javier Miralles · Last updated . How this site is made.
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