Terrarium Calculator
Calculate
Formula
Volume = pi x (diameter/2)^2 x height. Drainage layer = 1 inch of pebbles. Substrate = 1/3 of remaining height (charcoal 0.5" + soil). Volumes converted: cubic inches / 231 = gallons.
Frequently Asked Questions
How deep should terrarium substrate be?
The total substrate (including drainage) should fill about 1/3 of the container height. Use a 1-inch drainage layer of pebbles, a thin layer of activated charcoal, then potting soil on top.
Do I need a drainage layer in a terrarium?
Yes. Since most terrariums have no drainage holes, a 1-inch layer of pebbles or LECA at the bottom prevents root rot by allowing excess water to collect away from the soil.