🪴 Pot & Container Volume
Soil needed for round or square containers
About this calculator
The Pot and Container Volume calculator finds how much soil a planter holds. Enter the top diameter, bottom diameter, and height for tapered pots (or just diameter and height for straight sides); it computes the frustum volume in liters, gallons, and quarts, so you buy the right amount of potting mix.
Tip: add 10 percent for settling and top-dressing space — a pot filled to the brim spills soil every watering and leaves no room for mulch.