How Much Potting Soil Do I Need?
This potting soil calculator lets you measure the volume of soil needed for your container. Whether you want to set up a raised bed in the garden or arrange your blooming balcony, use the calculator to estimate how much soil to prepare. Choose from three container shapes, enter your dimensions, set the quantity — and get the answer in liters, gallons, cubic feet, and more.
Container Shape
There are many different container types on the market. Our potting soil calculator supports three shapes:
Rectangular (e.g., raised bed)
Volume of a rectangular cuboid:
V = depth × length × width
Round (cylinder)
Volume of a cylinder:
V = π × R² × depth, where R is the radius (= diameter ÷ 2)
Flower Pot (truncated cone)
Volume of a truncated cone:
V = (1/3) × π × depth × (r² + r × R + R²), where r is the bottom base radius and R is the top surface radius
Step-by-Step Example
- Choose the shape. Let's say you have flower pots — truncated cone shape.
- Enter the dimensions. Top diameter: 4 in, bottom diameter: 3.2 in, height: 2.75 in. Select Imperial units.
- Set the quantity. You want to plant oregano, basil, and thyme — enter 3 pots.
- Calculate. The calculator shows the total soil volume you need across all three pots.
You can also work in reverse: if you have a bag of soil and know the pot dimensions, you can estimate how many pots it will fill.
Important Notes
- The result is the volume for a completely full container. You may need less soil if the pot already has plant roots or if you only fill it to 4/5.
- Soil compresses differently depending on its type and how tightly you pack it — treat the result as a good estimate.
- Switch between metric (cm, liters, m³) and imperial (inches, gallons, ft³) units at any time.
FAQs
How do I determine the amount of potting soil I need?
The amount of potting soil depends on the volume of the pot and how full you want it. Choose the container shape, enter its dimensions, and the calculator does the rest. Compressing or loosening soil will also affect the actual amount needed.
How can I calculate potting soil for a terrace garden?
Use the Rectangular shape and enter your planter dimensions. For example, 5 rectangular pots of 24 × 18 × 10 cm each:
Soil = 24 × 18 × 10 × 5 = 21,600 cm³ ≈ 21.6 liters
How much soil do I need for a 30 cm round pot?
If the radius is 30 cm and depth is 10 cm:
V = π × 30² × 10 ≈ 28,274 cm³ ≈ 28.3 liters