# Kitten Growth Chart

What kittens weigh at each age, from DiGangi et al. (2019) — a study that measured two cohorts of kittens up to 20 weeks. The chart stops there; nothing is extrapolated past what the study measured.

| Weeks | Cohort | Average | ± 1 SD | n |
|---|---|---|---|---|
| 0 | Neonatal (longitudinal) | 0.11 kg | 0.02 kg | — |
| 2 | Neonatal (longitudinal) | 0.3 kg | 0.05 kg | — |
| 4 | Neonatal (longitudinal) | 0.48 kg | 0.1 kg | — |
| 6 | Neonatal (longitudinal) | 0.66 kg | 0.12 kg | — |
| 8 | Neonatal (longitudinal) | 0.92 kg | 0.14 kg | — |
| 6 | Pediatric (cross-sectional) | 0.69 kg | 0.14 kg | 31 |
| 8 | Pediatric (cross-sectional) | 1.02 kg | 0.18 kg | 609 |
| 10 | Pediatric (cross-sectional) | 1.22 kg | 0.26 kg | 298 |
| 12 | Pediatric (cross-sectional) | 1.45 kg | 0.34 kg | 206 |
| 14 | Pediatric (cross-sectional) | 1.73 kg | 0.43 kg | 80 |
| 16 | Pediatric (cross-sectional) | 1.93 kg | 0.46 kg | 54 |
| 18 | Pediatric (cross-sectional) | 1.83 kg | 0.24 kg | 4 |
| 20 | Pediatric (cross-sectional) | 2.18 kg | 0.4 kg | 28 |

The two cohorts overlap but do not agree: at 8 weeks the neonatal cohort averages 0.92 kg against 1.02 kg for the pediatric cohort — about 10% apart, from two different populations. The 18-week row is lower than the 16-week row before it because only 4 kittens were weighed at that age (against 54); the row is kept exactly as published. At 2 weeks the two published SOURCES disagree too: DiGangi et al. give a mean of 300 g while the ASPCA's own kitten weight chart publishes a ceiling of 295 g — a 1.7% gap. Past 10 weeks, weight stops reliably predicting age: accuracy within one week fell from 98.8% at two weeks to 17.9% at 20 weeks. This chart does not predict adult weight.

## Common questions

### How much should my kitten weigh?

At 8 weeks a kitten averages 1.02 kg, and at 12 weeks about 1.45 kg, in a study of 609 kittens at that age. Individual kittens vary widely — the chart shows the spread, not a target.

### Why does this chart stop at 20 weeks?

Because that is where the published data stops. DiGangi et al. measured kittens up to 20 weeks. Extending the curve past the measurements would be inventing numbers, so this chart ends where the study does.

### Can I tell my kitten’s age from its weight?

Up to about 10 weeks, reasonably well. After that the authors found weight often over- or underestimates age: their accuracy within one week fell from 98.8% at two weeks to 17.9% at 20 weeks. Past 10 weeks, teeth and eye colour tell you more than the scale.

### Will this tell me how big my cat will get?

No. This chart shows what kittens weigh while they are growing; it does not predict adult weight. No published study supports predicting an individual cat's adult weight from an early weight, so this site does not claim to.

### My kitten is outside the range — is something wrong?

Not necessarily. The range shown is one standard deviation around the average, so a healthy kitten can sit outside it. What matters more is the direction of travel over several weighings. A kitten that stops gaining, or loses weight, should be seen by a veterinarian.

## Sources

- Wikidata — dog breed mass (property P2067) — Wikimedia Foundation, query run 2026-07-22, CC0 license (https://query.wikidata.org/)
- Wikidata — cat breed mass (property P2067) — Wikimedia Foundation, query run 2026-07-28, CC0 license (https://query.wikidata.org/)
- Quantitative Translation of Dog-to-Human Aging by Conserved Remodeling of the DNA Methylome — Wang et al., Cell Systems, 2020, vol. 11, no. 2, p. 176–185.e6 (DNA methylation in 104 Labradors) (https://doi.org/10.1016/j.cels.2020.06.006)
- Body-Weight Changes during Growth in Puppies of Different Breeds — Hawthorne et al., Journal of Nutrition, 2004, vol. 134, p. 2027S (https://doi.org/10.1093/jn/134.8.2027S)
- Management of Reproduction — gestation period in the bitch — Merck Veterinary Manual, “Approximate Gestation Periods” table, accessed 2026-07-23 (https://www.merckvetmanual.com/multimedia/table/approximate-gestation-periods)
- Dystocia in Small Animals — Merck Veterinary Manual, “Diagnosis of Dystocia in Small Animals” section, accessed 2026-07-28 (https://www.merckvetmanual.com/reproductive-system/reproductive-diseases-of-the-female-small-animal/dystocia-in-small-animals)
- Factors affecting gestation duration in the bitch — Eilts et al., Theriogenology, 2005, vol. 64, no. 2, p. 242–251 (https://pubmed.ncbi.nlm.nih.gov/15955350/)
- Nutritional Requirements of Small Animals — energy requirements of the dog and cat — Merck Veterinary Manual, “Energy” section, accessed 2026-07-23 (https://www.merckvetmanual.com/management-and-nutrition/nutrition-small-animals/nutritional-requirements-of-small-animals)
- Chocolate Toxicosis in Animals — Merck Veterinary Manual, “Methylxanthine Content of Various Types of Chocolate” table and “Etiology” section, accessed 2026-07-28 (https://www.merckvetmanual.com/toxicology/food-hazards/chocolate-toxicosis-in-animals)
- ASPCA Poison Control — ASPCA, 24-hour emergency line, accessed 2026-07-28 (https://www.aspca.org/pet-care/aspca-poison-control)
- How old is your cat? — life stage and human equivalent age — International Cat Care (Cat Friendly Clinic), accessed 2026-07-28 (https://icatcare.org/resources/cat-friendly-clinic/how-old-is-your-cat-handout.pdf)
- The Special Needs of the Senior Cat — cat age in human years — Cornell Feline Health Center, Cornell University, accessed 2026-07-28 (golden-test source, not used to build the calculation) (https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/special-needs-senior-cat)
- Calorie Needs for an Average Healthy Adult Cat in Ideal Body Condition — WSAVA Global Nutrition Committee, updated July 2020 (golden-test source, not used to build the calculation) (https://wsava.org/wp-content/uploads/2020/07/Calorie-Needs-for-Healthy-Adult-Cats-updated-July-2020.pdf)
- Assessment of body weight for age determination in kittens — DiGangi et al., Journal of Feline Medicine and Surgery, 2019 (tables 1 and 2, weight-for-age, male and female) (https://doi.org/10.1177/1098612X19844846)
- Kitten Age & Weight Chart — ASPCA Pro, 2023 (golden-test source, not used to build the calculation) (https://www.aspcapro.org/sites/default/files/2023-08/aspca_kittenchart_2023.pdf)

Full method: https://caninecalculators.com/sources

_Verified 2026-07-28. Estimates only — this does not replace veterinary advice._