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FurCalc

Leopard Gecko Tank Size Calculator — Hatchling to Adult (Modern Standards)

What size tank does your leopard gecko need at each life stage? This calculator applies modern welfare standards — significantly larger than the 10-gallon pet-store minimum that’s still on many care sheets. Adults need a 20-gallon absolute minimum, 40-gallon long recommended, plus temperature gradient (88-92 °F basking, 75 °F cool), low-output UVB and three hides (warm, cool, moist). Husbandry baseline: ARAV educational resources.

Calculator

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Juvenile
30 gal (rec)
Min 20 · Ideal 40 · 30" × 12" × 12"

Setup essentials

  • Warm side: 90-95 °F surface temp (basking)
  • Cool side: 70-75 °F
  • Humidity: 30-40 %, with a moist hide (60-80 %)
  • UVB: optional but beneficial (2-5 % output, Ferguson zone 1-2)
  • Substrate: tile, paper towel or bioactive — never loose sand for young geckos (impaction risk)
Modern ARAV guidance favors larger enclosures for mental wellbeing. 40+ gallons for adults is now standard.

How to use the leopard gecko tank calculator

  1. Check life stage — Hatchling (10 gal), juvenile (20 gal), adult (40 gal recommended).
  2. Set thermal gradient — Warm 90–95 °F, cool 70–75 °F, nighttime 70–72 °F.
  3. Add 3 hides — Warm hide, cool hide, and moist hide (for shedding).
  4. Install UVB (recommended) — Low-output UVB (Arcadia ShadeDweller) improves long-term health.

Tank size by leopard gecko life stage

Life stageWeightTank minimum
Hatchling (0–3 months)3–10 g10-gallon long
Juvenile (3–12 months)10–40 g20-gallon long
Sub-adult (12–18 months)40–60 g20-gallon long or 40-gallon
Adult (18+ months)50–100 g40-gallon (36×18×18) recommended
Large adult male80–130 g40-gallon preferred

Leopard gecko husbandry terminology

Belly heat
Conductive heat through the substrate from below — leos digest with belly contact, unlike basking species.
Moist hide
Humid retreat (sphagnum moss or paper towel) for shedding; non-negotiable third hide.
Dust calcium
Light coating of calcium powder on feeder insects; weekly D₃ supplement covers UVB-light gaps.
Brumation
Winter slowdown lasting weeks to months; appetite drops, activity declines. Healthy in adults; stop feeding live until brumation ends.

Frequently Asked Questions

What size tank does a leopard gecko need?

Old pet-store minimum: 10 gallons. Modern ARAV-aligned welfare standard: 20-gallon long (30 × 12 × 12 in) minimum for adults, with 40-gallon (36 × 18 × 18 in) strongly recommended. Larger tanks provide proper thermal gradient (leopard geckos thermoregulate by moving between hot and cool zones) and room for 3 hides (warm, cool, moist) plus climbing/enrichment. 10-gallon setups are considered substandard and contribute to chronic stress and inadequate thermoregulation.

Do leopard geckos need UVB lighting?

Not strictly required for survival — leopard geckos have been kept without UVB for decades using calcium + vitamin D3 dietary supplementation. However, current ARAV research (Baines 2016) shows low-output UVB (Ferguson zone 1–2, 2–5 % UVB tubes) improves overall health, bone density, and coloration even for crepuscular species. Arcadia ShadeDweller or Zoo Med ReptiSun 5.0 on a 10–12 hour photoperiod is the modern recommendation.

What temperature do leopard geckos need?

Thermal gradient with warm-side under-tank heater + thermostat: warm-side surface 90–95 °F, warm-side ambient 85–88 °F, cool-side 70–75 °F, night 70–72 °F. Under-tank heaters (UTH) controlled by thermostat are standard — never use heat rocks (burn injuries) or unregulated heat pads. A digital probe thermometer at substrate level in warm and cool zones verifies actual temperatures.

Can leopard geckos live together?

Only females can sometimes cohabit, and never easily. Males always fight — never house two males. Male-female pairs lead to year-round breeding and egg-binding risk. Two females may tolerate each other in a 40+ gallon tank, but conflicts are common and subordinate geckos stop eating. Solo housing is safest. Never introduce adults together — fight injuries are immediate.

What about tail loss and regeneration?

Leopard geckos can drop their tail (autotomy) when stressed or grabbed — a survival mechanism. The regenerated tail grows back but looks different (bulbous, smooth, different color). Prevention: never grab by the tail, handle from below gently, minimize stress during new housing. The fat stored in the tail is a significant calorie reserve — post-drop geckos need extra food to recover.

What should leopard geckos eat?

Live insects only — leopard geckos are strict insectivores. Primary staples: crickets, dubia roaches, mealworms, Phoenix worms (BSFL). Occasional treats: waxworms, superworms. Always dust with calcium + D3 supplement at every feeding; calcium without D3 at alternate feedings. Juveniles: daily feeding. Adults: every other day or 2–3× weekly. Size prey 1/2 to 1× the distance between the gecko's eyes.

Sources & References

  1. [1]
  2. [2]
  3. [3]
    UVB Research (Baines 2016) — Arcadia Reptile
  4. [4]
    Leopard Gecko Husbandry — Merck Veterinary Manual