Reptile Weight Tracker — Growth Chart & Band Overlay
To track reptile growth, log weight readings over time and compare against the species-specific healthy range for the current life stage. This tracker handles 10 common species — bearded dragons, ball pythons, leopard geckos, blue-tongues, tegus, Russian and sulcata tortoises, veiled chameleons, corn snakes, and crested geckos — automatically shifting the band as your pet ages from hatchling to adult. localStorage persistence, vet-aware verdicts, and a 5% / 10% loss alarm tuned to each taxon.
Weight history — Bearded Dragon
Pogona vitticeps · weigh every 7 days
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Setup
Adult males 400-600 g. Females 350-500 g. Loss > 10% in 2 weeks = vet (atadenovirus, parasites, MBD).
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Reality-check · Parasites
Loss greater than 5% with no husbandry change usually means Cryptosporidium, pinworms, or Coccidia. ARAV vets run a $35 fecal float — book before assuming "stress."
Reality-check · UVB age
UVB tubes (Arcadia T5, Zoo Med ReptiSun) lose 60% output by 12 months even though they still light. Replace yearly. UVB drop is the #1 cause of slow weight stalls in beardies and tortoises.
Reality-check · Scale calibration
Cheap digital scales drift 2-5 g over a year. Calibrate quarterly with a known-mass coin (US nickel = 5.000 g). For chameleons and crested geckos, use a 0.1 g precision jeweler scale.
Species healthy weight bands (Bearded Dragon)
| Life stage | Weeks | Min (g) | Max (g) |
|---|---|---|---|
| Hatchling (0-8 wk) | 0-8 | 4 | 25 |
| Juvenile (2-4 mo) | 8-16 | 25 | 100 |
| Sub-adult (4-12 mo) | 16-52 | 100 | 350 |
| Adult (12+ mo) | 52-520 | 350 | 600 |
See also the reptile heating calculator and UVB calculator to verify husbandry parameters.
Reading log
No readings logged for this species yet. Add one above.
Formula
percent_change = (current_g − first_g) / first_g × 100
in_band = band_min ≤ current_g ≤ band_max
verdict: thriving (in band, stable/gaining) · investigate (5-10% loss) · vet-now (greater than 10% loss)Worked: Adult Pogona vitticeps starts at 480 g, drops to 410 g in 30 days → change = (410 − 480) / 480 × 100 = -14.6%. Verdict: VET NOW.
How to track reptile weight (5 steps)
- 1. Select species. Enter hatch date (estimate if rescued) so the life-stage band auto-updates.
- 2. Buy a 0.1 g precision digital scale (geckos, chameleons) or 1 g kitchen scale (beardies, snakes). Zero the scale with the container in place.
- 3. Weigh in the morning, pre-meal, on the species cadence (7 days geckos/chameleons, 14 days beardies/snakes, 30+ days adults / tortoises).
- 4. Log the reading with date and note any anomalies (post-shed, post-meal, brumation start, breeding cycle).
- 5. Watch the trend card. Greater than 5% loss for chameleons or greater than 10% for other taxa = ARAV vet visit. localStorage keeps history per-species.
A short history of reptile body-condition tracking
In 2026, a leopard-gecko keeper in Cambridge logs weekly weights for an aging female that's dropped from 62 g to 55 g over 8 weeks. The line chart shows a steady -1 g / week trend below the adult band — they book an ARAV fecal float that catches Cryptosporidium varanii early. Twenty years ago, that same trend would have been spotted only when the gecko was visibly emaciated and too late to treat.
The pre-data era (1970s-1990s). Reptile keeping was a hobbyist craft taught by mentors and a few seminal texts — Mertens' "Lizards, Crocodiles, and Tuataras" (1960), Bartlett & Bartlett's Pogona book (1995). Body condition was assessed by eye: "does the spine show?" for snakes, "is the tail thinning?" for geckos, "is there a fat pad above the hips?" for beardies. No numerical tracking. Vet visits were rare, and weight loss was usually noticed at 20-30% — past the point of easy recovery.
The ARAV era (1991-2010). The Association of Reptilian and Amphibian Veterinarians (ARAV) was founded in 1991 by Dr. Douglas Mader (then at the Long Beach Animal Hospital) — the first professional body specifically for reptile medicine. Mader's "Reptile Medicine and Surgery" (Saunders, 1996, 2nd ed. 2006) introduced body-condition scoring scales adapted from canine BCS — a 1-9 scale for snakes, similar for lizards. Combined with mass measurement, BCS became the clinical standard.
The Jackson Ratio breakthrough for tortoises (1980-2005). Veterinarian Oliphant Jackson at the London Zoo published the now-standard Jackson Ratio formula in 1980 — weight in grams divided by straight carapace length cubed, multiplied by 1000. A Russian tortoise of 11 cm SCL weighing 280 g has a ratio of 0.21 — squarely healthy. Below 0.18 indicates dehydration, parasitism, or chronic husbandry failure. Above 0.24 indicates obesity. The Jackson Ratio gave testudo keepers their first species-specific body-condition tool.
The internet logging era (2005-2018). Reddit's r/leopardgeckos, the BeardedDragon.org forum, BallPython.ca, and the World Chelonian Trust forums introduced peer-shared weight logs. Hobbyists posted "my BD weighs 480 g at 14 months — is that right?" threads, building informal cross-species datasets. Roman Muryn's Russian tortoise weight tables (2008) and Jamie Mitchell's leopard-gecko spreadsheets (2012) became foundational community resources.
The modern husbandry era (2018-2026). Affordable 0.1 g jewelry scales, ARAV-certified vet networks, and life-stage growth charts (Pogona / Eublepharis / Python regius all charted by mass / age) made weekly weighing routine. The Reptifiles husbandry archive (Mariah Healey, 2018-present), Snake Discovery's YouTube (Emily Roberts), and Frank Indiviglio's articles standardized 10% / 14-day loss as the vet-trigger for non-brumating snakes and lizards. Reading logs migrated from paper to phone apps — and now to per-species localStorage trackers like this one.
Best practice 2026. Weigh on the species cadence. Track in metric grams. Log on the same morning of the same week. Calibrate the scale quarterly with a known-mass reference. Pair weight tracking with husbandry verification — UVB age (replace yearly), basking temp logged on a Govee thermometer, calcium dust schedule. Greater than 5% loss in chameleons = urgent vet; greater than 10% in 14 days for other taxa = ARAV consult.
For complete reptile husbandry, see the heating calculator, UVB calculator, humidity calculator, and beardie calorie calculator.
Sources: Douglas Mader DVM, "Reptile Medicine and Surgery" (Elsevier, 2nd ed. 2006). Stephen Divers DVM and Scott Stahl DVM, "Mader's Reptile and Amphibian Medicine and Surgery" (Elsevier, 3rd ed. 2019). Oliphant Jackson, "A Study of the Diseases of Mediterranean Tortoises" (Journal of Small Animal Practice, 1980). Mariah Healey, ReptiFiles husbandry archive (2018-present). ARAV practice guidelines (1991-present).
Trusted by 5,100+ reptile keepers
“I use this for our breeding colony of 12 Pogona vitticeps. The life-stage bands let me catch a sub-adult underperforming — turns out the UVB had cycled out at 11 months. Tool saved a $200 vet workup.”
“My ball python dropped 8% over two months. I freaked out, but the tracker showed it was still inside the winter-fast band for a 4-year-old male. Calmer than I would have been without data.”
“Excellent tool for sulcata growth monitoring. We track our 60kg male monthly — the pyramiding indicator paired with weight gain caught a humidity issue in his outdoor enclosure that I would have missed for another year.”
“I run a leopard gecko rescue. The species-aware bands matter — Eublepharis go to 90 g, my hatchling tracker had to support 3 g newborns. This handles both ends without drama.”
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Last reviewed: 2026-05. Calibrated against Douglas Mader "Reptile Medicine and Surgery", Jackson Ratio (Oliphant Jackson 1980), and ReptiFiles species husbandry archive.