TCTopsoilCalc

Free container soil calculator

Potting Soil Calculator

This free soil calculator for pots estimates how much potting soil you need for one or more pots and planters. Choose a round, rectangular or tapered container and get liters, gallons, cubic feet and bags.

  • Choose the container. A flower pot may be cylindrical, rectangular or wider at the top.
  • Use the fill height. Measure the inside dimensions to the level where soil will stop.
  • Multiply the count. Enter how many matching containers you are filling.

Calculate potting soil

Measurement system
Container shape

Measure inside the container to the soil level, not the outside rim.

Total potting soil
58.7 L
US gallons15.5
Cubic feet2.07
Bags needed2

For 1 container. Bag count is rounded up.

How the soil calculator for pots works

The calculator estimates the interior volume of the container and then multiplies it by the number of matching pots. For tapered pots, it uses both the top and bottom diameters.

Rectangular planter = length x width x height
Round pot = pi x (diameter / 2)^2 x height
Tapered pot = pi x height / 12
  x (top diameter^2 + top x bottom + bottom diameter^2)
Total = one-container volume x quantity

Measure before you buy

  • Interior dimensions: measure inside the pot, where the soil actually sits.
  • Fill height: leave room for watering and mulch instead of measuring to the rim.
  • Drainage and filler: if the container has a large empty base, use the actual soil fill height.

Continue planning your soil project

Use the related tools for raised beds, open areas, replacement topsoil and soil removal.

Soil Volume CalculatorCalculate volume for a garden bed or area. Raised Bed Soil CalculatorPlan multiple beds and a custom soil mix. Topsoil CalculatorEstimate cubic yards, bags and tons for open areas. Topsoil Cost CalculatorCompare bulk delivery with bagged soil. Soil Removal CalculatorEstimate loose haul volume and truckloads. Free Supplier WidgetAdd a soil calculator to a supplier website.

Potting soil calculator FAQ

How do I calculate soil for a pot?

Measure the inside dimensions and calculate the container's volume. For a round pot, use pi times the radius squared times the fill height. Multiply by the number of matching pots.

Does a tapered flower pot use less soil?

Usually, yes, compared with a cylinder that has the same top diameter and height, because the bottom is narrower. Enter both diameters for a better estimate.

How many liters of soil do I need?

Use the result in liters, then divide by the liters in one bag and round up. Bag labels vary, so use the volume printed on your product.

Should I fill a pot all the way to the rim?

Usually leave some space for watering, mulch and settling. Measure the height you actually plan to fill rather than the full outside height.