How much soil do you need?
The amount of soil needed depends on the area you want to fill and the finished depth. Therefore, this soil calculator estimates volume in cubic feet, cubic yards, and cubic meters, plus bag count and an approximate weight based on the selected soil density.
How to use the soil calculator
- First, choose a rectangular area, circular area, or a total area you already know.
- Next, enter your measurements and select the matching units.
- Then, enter the soil depth.
- After that, choose a soil type for a planning estimate, or select Custom soil density and enter the value from your supplier.
- Finally, select the bag volume and, if needed, an extra allowance. Then select Calculate soil.
For irregular areas, divide the space into simple shapes, calculate each area, and add the areas together. Then, enter that sum using the total-area option.
Soil calculator formula
For a rectangular area:
Area = length × width
For a circular area:
Area = π × (diameter ÷ 2)²
For any area, convert the soil depth and area to compatible units, then calculate:
Volume = area × depth
Cubic yards = cubic feet ÷ 27
Cubic meters = cubic feet × 0.028316846592
Bags needed = volume in cubic feet ÷ bag volume, rounded up to a whole bag
Estimated weight = volume in cubic yards × selected density in US short tons per cubic yard
Additionally, the optional extra allowance is applied to volume before bag count and weight are calculated. One cubic yard equals 27 cubic feet. A US short ton equals 2,000 pounds.
Example soil calculation
For example, for a rectangular garden bed that is 9 feet long, 6 feet wide, and 6 inches deep:
- Area: 9 × 6 = 54 square feet
- Depth: 6 ÷ 12 = 0.5 feet
- Volume: 54 × 0.5 = 27 cubic feet
- Cubic yards: 27 ÷ 27 = 1 cubic yard
- 0.75 ft³ bags: 27 ÷ 0.75 = 36 bags
This is the geometric volume before any extra allowance. However, the bag count is exact for the selected bag volume; actual amounts needed can differ if the site is uneven or the soil settles after placement.
Why is the soil weight only an estimate?
Soil weight depends on its texture, organic matter, compaction, and moisture. For context, soil-science references describe bulk density as the dry mass of soil divided by its total volume, including pore spaces. Similarly, university extension sources also document differences in bulk density between soil textures and moisture conditions. Therefore, the soil-type presets are approximate planning values, not specifications for every product. For delivery limits or weight-based purchasing, use the density or unit weight supplied by the seller
Frequently asked questions
How many cubic feet are in a cubic yard of soil?
One cubic yard equals 27 cubic feet. Divide the volume in cubic feet by 27 to convert it to cubic yards.
How many bags of soil do I need?
Divide the required volume in cubic feet by the volume printed on each bag, then round up to the next whole bag. Check the actual package size before ordering.
Can I enter metric measurements?
Yes. The calculator supports meters and centimeters for dimensions and depth, square meters for total area, and liters for common bag sizes. Results include cubic meters as well as cubic feet and cubic yards.
Can I calculate soil for a circular bed?
Yes. Choose the circular-area option and enter the bed diameter. The calculator uses π times the squared radius to calculate the area, then multiplies that area by the soil depth.
Should I add extra soil?
An extra allowance may help with uneven ground, handling losses, or a project-specific settling allowance. The appropriate amount depends on the site and soil product; the calculator does not automatically include extra volume.
How accurate is the weight result?
The volume calculation follows the entered dimensions and unit conversions. Weight is an estimate because soil density varies. For the closest weight estimate, enter the density given by your supplier or use a measured bulk density.