Enter your bed size and pick a soil mix. You’ll get the volume, how many bags of each ingredient to buy and what it costs, compared with buying in bulk.
How much soil to buy
Soil needed35.2 cu ft
Cubic yards1.3
Bagged cost$240
Bagged raised bed soil
Amount
Bags
Cost
Raised bed soil (bagged mix)
35.2 cu ft
24 × 1.5 cu ft
$240
Buying in bulk: about 1.5 cubic yards for roughly $68 before delivery. Landscape suppliers usually sell in quarter- or half-yard steps.
How the calculator works
Volume is length × width × depth, converted to cubic feet. For round beds the area is π × radius². The total is multiplied by the number of beds, plus 10% for settling if that box is checked. Each ingredient’s share of the mix is then divided by the bag size and rounded up to whole bags.
Choosing a soil mix
Bagged raised bed soil is the easiest choice and is ready to plant. It is the most expensive per cubic foot for large beds.
Topsoil and compost is the most economical for big or deep beds, especially bought in bulk. Ask the supplier for screened topsoil.
Square foot gardening mix stays loose and holds moisture well, which suits shallow beds. Vermiculite makes it the priciest per cubic foot.
Whatever you choose, top up beds with 1 to 2 inches of compost each year to replace what settles and feeds the plants.
Frequently asked questions
How much soil do I need for a 4×8 raised bed?
A 4×8 ft bed that is 12 inches deep holds 32 cubic feet, or about 1.2 cubic yards. Adding 10% for settling brings it to about 35 cubic feet, which is 24 bags of 1.5 cubic feet.
How many cubic feet are in a cubic yard?
There are 27 cubic feet in a cubic yard. Bagged soil is sold in cubic feet; bulk soil from a landscape supplier is sold by the cubic yard.
Is it cheaper to buy soil in bags or in bulk?
For more than about one cubic yard, bulk is usually much cheaper per cubic foot, even with a delivery fee. Bags make sense for one or two small beds, or when you can’t get a truck close to the garden.
Why add extra soil for settling?
Fresh soil settles as it is watered and as organic matter breaks down, often by 10% or more in the first season. Buying a little extra saves a second trip, and you can top up beds with compost each year.
Can I fill the bottom of a deep raised bed with something cheaper?
Yes. Most vegetables root in the top 12 inches, so in beds deeper than that many gardeners fill the bottom with logs, branches and leaves. Enter only the depth of soil you plan to add.
A ready-to-use planting plan for one 4×8 ft raised bed with tomatoes, peppers, cucumbers, beans, lettuce, carrots, onions and radishes, square foot by square foot.
Three proven raised bed soil mixes compared, including topsoil and compost, the square foot gardening mix and bagged blends, with costs and what to avoid.