Soil Calculator: Calculate How Much Soil You Need
Calculate the soil volume required for garden beds, raised beds, planters, borders, containers, and other growing areas using accurate dimensions, soil depth, fill level, and material requirements.
Enter the shape, length or diameter, width, soil depth, and quantity of each growing area to calculate the required soil volume in cubic feet (ft³), cubic yards (yd³), and cubic metres (m³).
The Soil Calculator uses the selected bed dimensions to calculate area and volume, applies your chosen fill level and settling allowance, then divides the result into your selected blend of base soil, compost, and aeration material. You can use the result to estimate topsoil, garden soil, raised-bed soil, compost, soil conditioner, perlite, vermiculite, or other growing-medium quantities.
For a rectangular bed, measure the length × width × soil depth. For a round bed or planter, measure the diameter and soil depth. For a triangular area, measure the base × depth across × soil height. Add the quantity when you have multiple identical beds, then select the appropriate measurement units and material mix.
Soil Calculator
Beds, boxes & planters
Soil mix blend
Supply, liner & top-up
Cost estimate ($)
How the Soil Calculator Works
The Soil Calculator calculates the growing area, soil volume, material quantities, and purchasing requirements from the dimensions you enter. The calculator supports rectangular beds, round pots, and triangular areas, then applies soil depth, fill level, settling allowance, material blend percentages, and your selected supply method.
Enter your bed measurements first, then choose the soil depth, fill level, and soil blend. The calculator converts the selected units into a common measurement system, calculates the required volume, adds the selected settling allowance, and converts the result into cubic feet (ft³), cubic yards (yd³), cubic metres (m³), litres (L), bags, bulk loads, blocks, or wheelbarrow loads where applicable.
Soil Calculator Formula
The Soil Calculator uses a different area formula for each supported bed shape, then multiplies the calculated area by soil height. Fill level and settling allowance are applied to determine the amount of soil to purchase.
Rectangular Bed
Measure the length, width, and soil height for a rectangular garden bed or raised bed.
Area = Length × Width Volume = Length × Width × HeightRound Bed or Pot
Measure the diameter of the circular growing area and the required soil height.
Area = π × (Diameter ÷ 2)² Volume = Area × HeightTriangular Area
Measure the base, depth across the triangular area, and soil height.
Area = ½ × Base × Depth Volume = Area × HeightFinal Soil Volume
Soil to Buy = Gross Volume × Fill Level × (1 + Settling Allowance)The calculator uses the entered fill percentage between 10% and 100% and a settling allowance between 0% and 40%. The resulting volume is converted between cubic feet, cubic yards, cubic metres, and litres for practical soil ordering and material planning.
Soil Blend
The required soil volume is divided according to the selected base soil, compost, and aeration percentages.
Component Volume = Total Volume × Component %Bag Quantity
Bagged soil is calculated from the required volume and the volume of each bag, quart, or litre.
Bags = Required Volume ÷ Bag VolumeEstimated Weight
Soil weight is estimated from the blended material density and the calculated cubic-yard volume.
Weight = yd³ × Blend DensitySoil Calculator Example
Consider a raised garden bed with a rectangular shape measuring 8 ft long by 4 ft wide, filled to a 12-inch soil depth. The example below shows the main measurements and settings used to calculate soil volume, material quantities, supply requirements, and optional project costs.
Example Raised Garden Bed
Sample inputs for a complete soil volume and material calculation.
Helpful Information Before Using the Soil Calculator
Accurate measurements produce a more useful soil volume estimate. Measure the actual growing area and the depth of soil you intend to use rather than estimating the entire structure or container height.
Measure the Growing Area
Measure the inside length and inside width of rectangular garden beds, raised beds, planting borders, and soil-filled areas. For circular planters, measure the diameter across the widest point. For triangular areas, measure the base and perpendicular depth across the area.
Measure Soil Depth Correctly
Soil depth determines the vertical height used in the volume calculation. Enter the intended soil height in inches, feet, centimetres, or the available measurement unit, then use the same practical depth for the planting area being calculated.
Use Multiple Beds When Needed
Add separate rows when garden beds have different shapes, dimensions, soil depths, or quantities. Examples include an 8 × 4 ft raised bed at 12 inches deep, a 6 × 3 ft bed at 10 inches deep, and a circular planter with a 30-inch diameter.
Understand Fill Level
Fill level controls how much of the calculated bed volume is filled with the growing medium. A 100% fill level represents the complete calculated volume, while a lower percentage represents a partially filled bed or container.
Allow for Soil Settling
Newly added soil and organic growing media can settle after watering and use. The calculator lets you add a settling allowance so the purchasing quantity includes additional material for expected volume reduction.
Choose the Right Soil Blend
A soil blend can contain base soil, compost, and aeration material. Enter the desired percentages for each component; the calculator normalizes the proportions when the entered percentages do not total exactly 100%.
Check Bag Volume
Soil bags are sold in different volumes and units. Common measurements include cubic feet (ft³), litres (L), and quarts (qt). Use the actual volume printed on the product label rather than assuming every bag contains the same amount of soil.
Plan Bulk Soil Delivery
Bulk soil is commonly ordered by cubic yard (yd³) or cubic metre (m³). Enter the minimum order and truck capacity when applicable so the calculator can estimate rounded bulk quantities and delivery loads.
Consider Soil Weight
Soil weight varies according to material density, moisture content, organic matter, compost content, and the selected growing medium. The calculator provides an estimated weight using the density assigned to the selected materials and reports the result in pounds (lb), United States tons, and kilograms (kg).
Use the Liner and Top-Up Options
The optional liner calculation estimates the surface coverage required for the bed based on its area, perimeter, and soil height. The yearly top-up option estimates additional soil volume required to replenish a specified depth across the growing area.
Check Unit Conversions
- Use feet and inches for common raised-bed measurements.
- Use cubic feet for bagged soil volume.
- Use cubic yards for bulk soil orders.
- Use cubic metres for metric bulk material orders.
- Use litres for smaller growing-medium quantities.
- Use pounds and kilograms when estimating material weight.
Review the Final Quantity
Treat the calculated quantity as a project estimate based on the measurements and material settings entered. Product packaging, supplier minimums, material density, moisture, compaction, delivery requirements, and actual bed construction can change the final amount purchased.
Frequently Asked Questions
Find quick answers to common questions about soil volume, garden beds, raised beds, soil depth, bags, bulk soil, compost, soil blends, and material quantities.
How does the Soil Calculator calculate the amount of soil I need?
The Soil Calculator calculates the area of your growing space, multiplies that area by the required soil height, applies the selected fill level and settling allowance, and converts the final volume into practical purchasing units. The result can be displayed in cubic feet (ft³), cubic yards (yd³), cubic metres (m³), and litres (L), with additional estimates for bags, bulk loads, blocks, and wheelbarrow loads.
What measurements do I need for a rectangular garden bed?
You need the length, width, soil height, and quantity. For example, an 8 ft long × 4 ft wide raised bed with a 12-inch soil depth and a quantity of 1 provides the dimensions required for the calculation. The calculator converts the selected units before calculating the soil volume.
Can the Soil Calculator calculate soil for a round planter?
Yes. Select the round pot option and enter the diameter and soil height. The calculator uses the circular area formula, π × radius², and multiplies the area by the soil height to determine the required soil volume.
Can I calculate soil for multiple garden beds?
Yes. Add separate bed rows when you have different growing areas, shapes, dimensions, soil depths, or quantities. Examples include two 8 × 4 ft raised beds, one 6 × 3 ft vegetable bed, and three circular planters with different diameters.
What is the settling allowance in the Soil Calculator?
The settling allowance adds extra soil to account for the reduction in soil volume after placement, watering, and settling. The calculator allows a settling allowance from 0% to 40%, so a 10% allowance increases the purchasing quantity by 10% after the selected fill level is applied.
How many bags of soil do I need?
Divide the required soil volume by the volume of one bag and round the result up to the next whole bag. For example, 35.2 ft³ of required material divided by 1.5 ft³ per bag produces 23.47 bags, so you would purchase 24 bags.
Can the calculator estimate soil weight in pounds and kilograms?
Yes. The calculator estimates material weight from the calculated cubic-yard volume and the density assigned to the selected base soil, compost, and aeration materials. The result is provided in pounds (lb), United States tons, and kilograms (kg).
Can I calculate a soil mix containing topsoil, compost, and aeration material?
Yes. Enter the percentage for base soil, compost, and aeration material. The calculator divides the required volume between the three components and reports the estimated volume of each component separately.
What is the difference between cubic feet, cubic yards, and cubic metres for soil?
Cubic feet (ft³), cubic yards (yd³), and cubic metres (m³) are volume measurements used for different purchasing situations. Bagged soil is frequently labeled in cubic feet or litres, while bulk soil is commonly sold by cubic yard or cubic metre. The calculator provides conversions so you can compare your calculated requirement with supplier packaging and delivery quantities.