Terrarium Humidity Control Calculator

Mistings per day depends entirely on Ventilation Type and nothing else — Enclosure volume, Target humidity, and Ambient room humidity have zero effect on it. That's because the calculator assumes each misting boosts humidity by a fixed 20 percentage points, and then asks only how quickly that boost decays back down given the enclosure's ventilation (a sealed setup with vents loses humidity slowest, a full screen top fastest), spread across 14 assumed active hours per day. Ventilation Type alone sets that decay rate, so it alone sets the misting frequency. Enclosure volume and the humidity gap between Target humidity and Ambient room humidity instead drive Water per misting (oz), and both push it in one direction only: a bigger enclosure or a wider humidity gap always raises it, a smaller enclosure or narrower gap always lowers it — a real reversal doesn't happen for either.

Which of the two moves it more depends on how you measure "more": a percentage-point change in Target humidity swings the figure harder near the default settings than the equivalent percentage change in Enclosure volume does, but Enclosure volume's own input range spans a 100x width (5 to 500 gallons) versus humidity's much narrower 0-100 percentage-point ceiling, so across their full input ranges Enclosure volume can move the figure further in absolute terms. Neither framing is "more correct" — they're answering different questions, and this calculator doesn't crown one input the single biggest driver of Water per misting. Misting duration (sec) is derived directly from Water per misting, floored at a minimum 5 seconds so very small water amounts still register as a real misting session rather than an instantaneous one. This is a planning heuristic built on stated rule-of-thumb decay rates and boost sizes (documented in the engine's own comments), not a measurement of your specific enclosure's actual humidity behavior — real terrariums vary by substrate moisture, live plants, and airflow patterns this calculator has no way to observe.