Leopard Gecko Calcium Guide: Dusting, D3, and Ratios
| Plain calcium | Most feedings |
| Calcium + D3 (no UVB) | ~Weekly |
| Risk of overdose | Mainly from excess D3, not plain calcium |
Why calcium matters so much
Leopard geckos are prone to metabolic bone disease if calcium intake is insufficient relative to phosphorus, and most feeder insects on their own have a poor calcium-to-phosphorus ratio — dusting corrects for that gap at the point of feeding.
Plain calcium vs calcium with D3
Plain calcium (no D3) can be used at most feedings without an overdose concern. Calcium with D3 helps the body actually absorb and use that calcium, but D3 itself can build up to toxic levels if overused — which is why it's typically limited to roughly once a week for geckos without UVB.
If your gecko has UVB
With adequate low-level UVB exposure, a gecko can synthesize its own D3, so many keepers reduce or skip the separate D3 dusting and rely mostly on plain calcium, since the risk of D3 toxicity is more about dietary excess than sunlight/UVB exposure.
How to dust correctly
Add feeders to a small container with a light dusting of powder and gently shake to coat them, then offer immediately — dusting insects long before feeding lets much of the powder fall off before the gecko eats them.
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A single adult leopard gecko needs a 20-gallon long tank as an absolute minimum, with a 36x18 in (40-gallon breeder) footprint now considered the recommended standard — plus a secure lid, an under-tank heater on a thermostat, a thermal gradient, at least three hides, and a shallow water dish.
Set up in this order: substrate, then heat source wired through a thermostat, then hides and water dish, then decor — and run the whole enclosure for at least 24–48 hours to confirm stable temperatures before your gecko moves in.
Hatchlings can start in a 10-gallon tank or tub, juveniles do well in 20 gallons, and adults need a 20-gallon long as an absolute minimum — with 36x18 in (40-gallon breeder) now the widely recommended standard, not just an upgrade.
Heat a leopard gecko enclosure with an under-tank heater and/or overhead heat source (halogen or deep heat projector) wired through a thermostat — a thermostat is mandatory, not optional, and heat rocks should never be used.
Leopard geckos can survive without UVB using dietary D3 supplementation, but current husbandry guidance now recommends low-level UVB (roughly 2–6% T5) as best practice — it improves D3 synthesis, bone density, and natural behavior, and views on it have shifted significantly from older nocturnal-species advice.
Keep ambient humidity around 30–40% across most of the enclosure, with a dedicated humid hide raised to roughly 70–80% to support smooth, complete sheds.