Terrarium Calculators
Free terrarium calculators for substrate layers, plant counts, lighting, and humidity.
Tools for terrarium builders and vivarium enthusiasts.
Layer depths, planting density, lighting and humidity. 9 calculators for terrariums and bioactive vivariums. Aquatic setups sit under Aquarium.
Drainage layer is sized as a fraction of container height rather than a fixed depth, because a terrarium has no drainage holes and the layer is a reservoir, not a filter. Closed tropical builds take a quarter of the height. Open ones take a fifth, since evaporation does part of the work. Succulents take a full third, which surprises people who assume dry plants need less drainage. They need more, because they tolerate standing water least of all.
UVB distance uses the Ferguson zone system, and it is the number to get right if anything lives in the enclosure. Zones run from 0 to 0.7 UV Index for nocturnal geckos up to 6.0 to 9.7 for uromastyx and desert lizards. Too little causes metabolic bone disease. Too much burns eyes. Output at 30 cm varies by nearly six times across the common bulb types, so the fixture matters as much as the mounting height.
Misting and heat gradient pages assume a lid. An open bowl behaves differently.
Terrarium Grow Light Wattage Calculator
Calculate grow light watts for a terrarium by volume and plant type. Get LED watt recommendations for low-light, tropical, and high-light setups.
Terrarium Heat Gradient Calculator
Plan a reptile heat gradient from basking and cool end targets. Returns warm side and mid-enclosure air temperatures, plus a check that the tank is long enough.
Terrarium UVB Distance Calculator
Find the correct UVB bulb distance for your reptile. Enter species UV index requirement and bulb type to get the safe basking distance in inches and cm.
Terrarium Activated Charcoal Layer Calculator
Calculate the activated charcoal volume needed for a terrarium based on vessel diameter, depth, and layer thickness. Includes drainage tips.
Bioactive Terrarium Cleanup Crew Calculator
Calculate isopods and springtails needed for a bioactive terrarium from enclosure size and species. Returns starting colony size and substrate volume needed.
Terrarium Drainage Layer Calculator
Calculate drainage layer depth and volume for your terrarium from footprint dimensions. Returns LECA, gravel, or foam volume to prevent root rot.
Terrarium Misting Schedule Calculator
Work out how often to mist a terrarium and how much water each session needs, from its volume, lid type, plant group, and the humidity of the room.
Terrarium Plant Count Calculator
Calculate plant count for your terrarium from dimensions and type. Returns count for mosses, ferns, succulents, and tropical plants with spacing guidelines.
Terrarium Substrate Layer Calculator
Calculate the depth and litres of every terrarium layer: drainage, charcoal, growing medium and top dressing, from your container size and build type.