Materials
Soil Calculator
How much soil a bed, planter or border needs, at the depth your plants want.
Volume needed
cubic yards
- Cubic feet
- 240cu ft
- Cubic metres
- 6.8m³
- Area covered
- 240ft²
- Weight
- tonsAdd a density to get tons. Your supplier has the figure for the exact product.
The working
Area = Length × Width
= 20 ft × 12 ft
= 240 ft²
Volume = Area × Depth
= 240 ft² × 1 ft
= 240 cu ft
Cubic yards = Cubic feet ÷ 27
= 240 ÷ 27
= 8.89 cu yd
1 cubic yard = 3 ft × 3 ft × 3 ft = 27 cubic feet
Enter the bed and the finished soil depth. Depth here is a growing decision rather than a grading one — shallow for turf and annuals, deeper for shrubs and vegetables — so the calculator defaults to a bed depth rather than a dressing.
How this calculator works
- Formula version
- 1.0.0
- Last reviewed
- 2026-09-01
- External data
- None
This tool uses only your inputs and exact unit conversions. No benchmark, average or market figure is built into it. How we calculate
What this calculates
The volume of soil needed to fill a bed, border or planter to a chosen finished depth, in cubic yards and its equivalents.
Choosing a depth
Depth here is set by what you are growing rather than by a grade. Turf and shallow annuals need less; shrubs and vegetables root deeper. Under about six inches, most plants beyond turf struggle.
For a raised bed, measure the internal depth you intend to fill, not the height of the frame — most beds are not filled to the rim.
Why tons need a density from you
Bagged and bulk blends differ, and moisture moves the weight substantially. The density field stays empty and takes the supplier figure for the exact mix.
Worked example
Four raised beds, each 8 ft × 4 ft, filled 12 in deep
- Bed size
- 8 ft × 4 ft
- Depth
- 12 in
- Number of beds
- 4
- Area of one bed= 8 ft × 4 ft= 32 sq ft
- Volume of one bed= 32 sq ft × 1 ft= 32 cu ft
- Total volume= 32 cu ft × 4= 128 cu ft
- Cubic yards= 128 ÷ 27= 4.74 cu yd
- Constant depth across the bed, with vertical sides.
- The volume is the finished, settled volume you want in place.
- Unit conversions are exact.
- Density and price are used only if you enter them.
- It does not allow for settlement. Fresh blends with high organic content settle over the first season; many gardeners overfill slightly to compensate.
- It does not assume a density, so it cannot give tons on its own.
- Irregular beds have to be split into rectangles and circles and added.
Common questions
- How much soil do I need for a raised bed?
- Multiply the internal length by the width by the depth you intend to fill, then divide the cubic feet by 27. Enter the bed above and set the number of identical beds to get the total in one step.
- How deep should soil be in a raised bed?
- It depends on what you are growing — root depth is the driver. Turf and shallow annuals need less than shrubs and vegetables. Below about six inches most plants beyond turf will struggle.
- What is the difference between this and the topsoil calculator?
- This one fills a bed to root depth. The topsoil calculator spreads a shallow, even dressing over an existing surface, which is a different job at a different depth.
Where people go next
All materials tools →Ordered by what usually comes next in the same job, not by keyword.