Potting Soil Volume Calculator
Calculate how much potting soil you need for containers and planters using the cylinder volume formula (πr²h).
Potting Soil Volume Calculator
Calculate how much potting soil you need for containers and planters
Formula
V = πr²h (cylinder) or V = L×W×H (rectangular)Volume calculated based on container shape and dimensions
How to Use
- 1Select container shape — Choose round, rectangular, or tapered pot shape.
- 2Enter dimensions — Input diameter/length, width, and height of your container.
- 3Adjust fill level — Set fill percentage (leave room for watering).
- 4View results — See volume in gallons, quarts, liters, and bags needed.
Frequently Asked Questions
How do I measure a tapered pot?
Measure the diameter at the top rim and at the bottom inside. The calculator uses the frustum formula to account for the taper.
Should I fill the pot completely?
Leave 1-2 inches from the rim for watering. Use 90-95% fill for most containers.
What size bag should I buy?
For small pots, 8-quart bags are convenient. For multiple large containers, 2 cubic foot bags are more economical.
Do I need drainage material at the bottom?
Modern advice says no - it can actually impede drainage. Just ensure your pot has drainage holes and use quality potting mix.