Bearded dragon
Bearded dragon tank size chart
By life stage, in inches, centimeters and gallons - and with the disagreement between the market standard and the current published minimum stated rather than hidden.
By Brijon M.Last updated
Hatchling: 36 x 18 x 18 in as a grow-out. Juvenile: 48 x 24 x 24 in. Adult: 48 x 24 x 24 in is the floor and 6 ft L x 2 ft W x 2 ft H (1.8 x 0.6 x 0.6 m), or 24 cubic feet of internal volume is the current published minimum, with 4x2x2 accepted for individuals that stay under about 18 inches total length.
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The chart
| Life stage | Minimum dimensions | Approx. cm | Approx. gallons |
|---|---|---|---|
| Hatchling (under 10 in) | 36 x 18 x 18 in grow-out, moved up early | 90 x 45 x 45 cm | ~40 gal |
| Juvenile (10-16 in) | 48 x 24 x 24 in | 120 x 60 x 60 cm | ~120 gal |
| Small adult (up to about 18 in total length) | 48 x 24 x 24 in is acceptable | 120 x 60 x 60 cm | ~120 gal |
| Adult (19-23 in average total length) | 72 x 24 x 24 in, or 24 cubic feet internal volume | 180 x 60 x 60 cm | ~180 gal |
Where the sources disagree, and why we show both
ReptiFiles currently sets the adult minimum at 6 x 2 x 2 ft or 24 cubic feet. The derivation is stated: an enclosure should be at least three times the lizard's total length and 24 inches tall, and bearded dragons average 19 to 23 inches total length. The same page documents the standard rising repeatedly - from 36 x 18 x 18 in, to 48 x 18 x 21 in, to 48 x 24 x 24 in - as each previous figure proved inadequate for thermoregulation and exercise, and describes the current figure as a compromise intended to push US keepers toward a better standard without, in its words, shocking the system.
Meanwhile the US market sells 4x2x2 as the adult bearded dragon enclosure, and the same source accepts it for individuals that do not grow past about 18 inches.
Our working position: 48 x 24 x 24 in is a hard floor, 72 x 24 x 24 in is the target for a full-size adult, and anything below 4x2x2 is a standard that has already been abandoned twice. We state both numbers because pretending the hobby has settled on one would be the less honest option.
Why the number is about thermoregulation, not space to roam
The reason a short enclosure fails is specific. A bearded dragon needs a basking surface at 108-113 F (42-45 C) surface temperature and a cool side at 77-85 F (25-29 C) surface, 72-99 F (22-37 C) air gradient simultaneously. The published air gradient runs 72-99 F (22-37 C) air gradient. You cannot establish that spread over three feet with a lamp powerful enough to hit 113 F at the hot end - the whole box warms. The length is what buys you the gradient.
Height matters for a reason people miss
24 inches of height is part of the published minimum, and it is not about climbing. The Arcadia Desert 12% lamp needs about 11 inches above the basking surface through mesh. Add the height of the basking platform and the animal itself and a shallow enclosure has nowhere to put the lamp at its correct distance. The distance figures are here.
What to buy once you have the number
The 4x2x2 floor
Zen Habitats 4x2x2 PVC Reptile Enclosure
Front-opening PVC at 48 x 24 x 24 in, with a mesh top that puts a T5 fixture at a workable distance. The right call for a small adult, and the minimum for any adult.
If you want the extra volume
Zen Habitats 4x2x4 PVC Reptile Enclosure
48 inches of height gives a second level and more thermal headroom, at the cost of a harder gradient to control.
The full enclosure roundup ranks against exactly these figures, and the 40 gallon versus 120 gallon comparison covers the most common upgrade decision.
Frequently asked questions
What size tank does a bearded dragon need?
48 x 24 x 24 in is the floor for an adult; the current published minimum is 6 ft L x 2 ft W x 2 ft H (1.8 x 0.6 x 0.6 m), or 24 cubic feet of internal volume, with 4x2x2 accepted for individuals under about 18 inches total length.
Is a 120 gallon tank big enough for a bearded dragon?
A 120 gallon is typically 48 x 24 x 24 in, which is the floor rather than the target. It is acceptable for a small adult and below the current published minimum for a full-size one.
What size tank for a baby bearded dragon?
A 36 x 18 x 18 in grow-out works, moved up early. Many keepers go straight to the adult enclosure with plenty of cover, which avoids buying twice.
How big do bearded dragons get?
An average total length of 19 to 23 inches, which is the figure the three-times-length sizing rule is derived from. Some individuals stay under about 18 inches.
Sources
- Bearded Dragon Terrarium Size Requirements — ReptiFiles
- Bearded Dragon Temperatures & UVB Requirements — ReptiFiles
Read next
Hub
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A 4x2x2 is the standard most of the hobby works to. The current published minimum is larger than that. Here is what the numbers actually say, and what to buy once you know them.
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Guides
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Minimum enclosure footprints by species and life stage, in inches, cm and gallons.
Lighting & heat
UVB distance and Ferguson zones
Ferguson zones with published UVI ranges and the mount distance for every lamp class.