Raised Bed Soil Calculator (Cubic Feet, Yards and Bags)
Enter your bed size to see how many cubic feet, cubic yards and bags of soil you need, for one bed or several, rectangular, round or L-shaped.
Pick a preset or enter custom dimensions below
Most vegetables need at least 6 to 12 inches of soil
Old soil, logs or cardboard already in the bed. New soil fills the top 12 inches; enter 0 for an empty bed
New soil settles, so some gardeners buy a little extra to top up
60% topsoil, 40% compost. Great all-purpose mix.
You Need
Soil Mix Breakdown
Bed area: 32.0 sq ft · Perimeter: 24.0 ft
Bagged Soil and Mix Ingredients
Once you know your cubic feet, divide by the bag size on the label. These are widely sold bags for each part of a raised bed fill.
Ready-made raised bed mix
FoxFarm Raised Bed Planting Mix, 1.5 cu ft
A pre-blended raised bed mix with earthworm castings. Use the 1.5 cu ft bag count above.
Check price on AmazonCompost for any mix
Back to the Roots Organic Compost, 1 cu ft
Peat-free organic compost in a 1 cu ft (25.7 qt) bag. Round the Compost line in your result (cu ft) up for the bag count.
Check price on AmazonMel's Mix: the peat or coir third
Back to the Roots Organic Coir, 51 qt
A compressed coco coir brick that expands to 51 quarts, about 2 cubic feet. Coir is the common peat moss swap.
Check price on AmazonMel's Mix: the vermiculite third
Palmetto Vermiculite, 4 cu ft (Medium)
Listed as Medium; the listing describes it as grade 3 coarse vermiculite. 4 cu ft bag: divide the vermiculite line in your Mel's Mix result by 4 for the bag count.
Check price on AmazonAs an Amazon Associate PlantingCalc earns from qualifying purchases. Picks are based on product listings and published specs.
How Much Soil for Common Raised Bed Sizes
Volume is length x width x depth. Bag counts are rounded up; add a little extra for settling.
| Bed size | Depth | Cubic feet | Cubic yards | 2 cu ft bags | 1.5 cu ft bags | 40 lb bags |
|---|---|---|---|---|---|---|
| 4 x 8 ft | 6 in | 16.0 | 0.59 | 8 | 11 | 22 |
| 4 x 8 ft | 10 in | 26.7 | 0.99 | 14 | 18 | 36 |
| 4 x 8 ft | 12 in | 32.0 | 1.19 | 16 | 22 | 43 |
| 4 x 4 ft | 6 in | 8.0 | 0.30 | 4 | 6 | 11 |
| 4 x 4 ft | 10 in | 13.3 | 0.49 | 7 | 9 | 18 |
| 4 x 4 ft | 12 in | 16.0 | 0.59 | 8 | 11 | 22 |
| 3 x 6 ft | 6 in | 9.0 | 0.33 | 5 | 6 | 12 |
| 3 x 6 ft | 10 in | 15.0 | 0.56 | 8 | 10 | 20 |
| 3 x 6 ft | 12 in | 18.0 | 0.67 | 9 | 12 | 24 |
Common questions
The amount of soil depends on your bed dimensions. Multiply length x width x depth (all in feet) to get cubic feet. For example, a 4x8-foot bed that is 12 inches deep needs 32 cubic feet of soil. Divide by 27 to convert to cubic yards if ordering in bulk. Our calculator above handles all the math for you, including multiple bed shapes and soil mix breakdowns.
How This Calculator Works
This calculator computes soil volume using standard geometric formulas: length × width × depth for rectangular beds, π × r² × depth for round beds, and the sum of two rectangles for L-shaped beds. One cubic yard is 27 cubic feet. Bag counts divide the total by the bag volume printed on the bag and round up. A 40 lb bag of topsoil usually holds about 0.75 cubic feet, but bag sizes vary, so check the label. For several beds, compare the bag count with a bulk delivery priced by the cubic yard.
Tips for Filling Raised Beds
- In a deep bed, some gardeners lay logs, sticks or leaves in the bottom (the hugelkultur method) so less soil has to be bought. Enter that depth under Already Filled at the Bottom.
- A common mix is 60% topsoil and 40% compost (the Standard Mix preset). Mel's Mix (⅓ compost, ⅓ peat, ⅓ vermiculite) is popular for square-foot gardening; the breakdown above lists each part in cubic feet.
- New soil settles during the first season, so expect to top it up with compost. The Extra for Settling option adds a margin to your order.
- Once your bed is filled, use our planting date calculator to find the best time to plant in your zone, then check seed spacing to maximize your harvest.
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Quick answer▾
How much soil for a raised bed? A 4 x 8 ft bed 12 inches deep holds 32 cubic feet (1.2 cubic yards): 16 bags of 2 cu ft, 22 bags of 1.5 cu ft, or about 43 bags of 40 lb topsoil. The formula is length x width x depth in feet; divide by 27 for cubic yards.
Data last updated: October 2026