Bearded Dragon Size & Care Calculator
Enter your bearded dragon's age in months and we will estimate its expected size and lay out the right tank size, basking temperatures, feeder insect size, the insect-to-greens ratio, and how often to feed for its life stage. Want to know what one costs? See the cost of a bearded dragon.
Not sure? Estimate from when you got your dragon, or use its hatch date if you know it. For age in years, multiply by 12.
Baby
0 to 3 months
Juvenile
3 to 12 months
Adult
12 months +
Care Plan
Snout to tail tip, typical range
Cool end stays 75 to 85F for every age
Never larger than the space between the eyes
Offer fresh greens daily at every age
These figures are general guidance for Central (inland) bearded dragons based on reptile-vet and breeder best practices. Every dragon is an individual. For health concerns, weight loss, or a dragon that is not growing, consult a reptile or exotic veterinarian.
Gear for this life stage
Track it all as your dragon grows
The Bearded Dragon Care Planner includes a weight & growth tracker, temperature & UVB log, and a feeder insect & supplement schedule, plus 7 more printable worksheets.
Get the Planner for $39How Bearded Dragon Care Changes With Age
A bearded dragon's needs shift dramatically over its first year. A hatchling is a tiny, fast-growing insectivore that needs hot basking temperatures and several feedings a day. By its first birthday it is a near-adult that eats mostly greens, basks cooler, and settles into a calmer routine. Matching your husbandry to your dragon's life stage is one of the most important things you can do, and it is exactly what this calculator is built to help with.
Babies (0 to 3 months)
Hatchlings are usually 3 to 9 inches long and grow astonishingly fast. They eat appropriately sized insects three to five times a day, with greens offered fresh daily even if they are mostly ignored at first. Dust insects with calcium at nearly every feeding. Babies bask hot, around 100 to 110F, with a cool end of 75 to 85F. A 20-gallon long works to start, but add plenty of hides and clutter so the space does not feel exposed.
Juveniles (3 to 12 months)
Through the juvenile months your dragon does most of its growing, often reaching 11 to 20 inches. Feed insects one to three times a day while gradually increasing the share of greens. Basking temperatures ease down to roughly 95 to 105F. This is the right time to move into a 40-gallon breeder if you have not already, since a cramped enclosure can stunt growth and stress a young dragon.
Adults (12 months and older)
Adults reach roughly 16 to 24 inches and flip to a greens-forward diet, about 80 percent plants and 20 percent insects, to avoid obesity. Offer insects every other day or a few times a week, and keep greens available daily. Basking settles to about 90 to 100F. The 40-gallon breeder is the absolute minimum, but 75 to 120 gallons gives an adult room to roam and thermoregulate properly. Replace UVB bulbs every 6 to 12 months and schedule a yearly wellness check with a reptile vet. Never house two dragons together, as they are territorial and will fight.
Want the full picture? Browse our detailed guides:
Frequently Asked Questions
How accurate is the expected size for my bearded dragon?
The size ranges are typical growth figures for healthy Central (inland) bearded dragons, the species most commonly kept. Real growth depends on genetics, diet, lighting, and enclosure size. A dragon that is a little under the range is not automatically unhealthy, but a dragon well below it, or one that has stopped growing early, is worth discussing with a reptile vet, since stunting often points to poor UVB, low temperatures, or an insect-light diet.
What tank size does a baby bearded dragon need?
A hatchling can start in a 20-gallon long, but most keepers move to a 40-gallon breeder within a few months, and many simply start there with extra hides and clutter so the space is not overwhelming. The 40-gallon breeder is the lifelong minimum for an adult, with 75 to 120 gallons strongly preferred. Bigger is almost always better as long as the dragon can still find its food and basking spot.
Why are basking temperatures higher for babies?
Young, fast-growing dragons digest large amounts of insect protein and need more heat to do it, so babies bask around 100 to 110F. As a dragon matures its metabolism slows and its basking needs drop, with adults comfortable around 90 to 100F. The cool end of the enclosure should stay 75 to 85F for every age so your dragon can thermoregulate. At night no heat is needed as long as the room stays above about 65F.
How do I know if a feeder insect is the right size?
The classic rule is that no feeder insect should be larger than the space between your dragon's eyes. Anything bigger is a choking and impaction risk, especially for babies and juveniles. When in doubt, size down. The calculator gives a general size range by age, but always check it against your individual dragon's head.
Why do adults eat mostly greens and babies mostly insects?
Babies and juveniles are growing rapidly and need the protein, so their diet runs roughly 70 to 80 percent insects and 20 to 30 percent greens. As a dragon matures the ratio flips to about 80 percent greens and 20 percent insects, because an adult on a high-insect diet easily becomes obese and can develop fatty liver disease. Greens should be offered fresh every day at every age.
How often should I dust feeder insects with calcium?
For babies and juveniles, dust insects with plain calcium (no D3) at most feedings, and use a calcium with D3 or a multivitamin a couple of times a week. Adults generally need calcium dusting a few times a week. Calcium plus proper UVB is what prevents metabolic bone disease, the most common serious illness in captive dragons. Exact dosing varies, so confirm a schedule with your reptile vet.
My dragon is older than 18 months. Is it fully grown?
Most bearded dragons reach their adult length of roughly 16 to 24 inches by 12 to 18 months, though they continue to fill out and gain weight until around two years. Once your dragon is in the adult stage, care stays consistent: a greens-forward diet, calcium dusting, stable temperatures, fresh UVB every 6 to 12 months, and a yearly wellness check with a reptile vet.