Kitten Growth Chart by Month: Average Weight and Height

WeightQ&AMeongsiljang Veterinary Advisory Board

We’ve put together an easy-to-read guide showing the average monthly weight and height for kittens from 1 to 12 months of age, along with key care tips for each stage of growth.

What Is a Kitten Growth Chart by Month?

A female kitten being weighed on a scale

The kitten growth chart by month of age is a reference guide that outlines the average weight and body length of cats from one to twelve months of age. It serves as the most basic indicator to check if your kitten is growing at a similar pace to its peers, or if it is growing too slowly or too rapidly. It is especially important to weigh and record your kitten’s weight weekly until it reaches six months of age, as the growth rate during this period lays the foundation for lifelong health.

Why Is Monthly Monitoring Important?

A kitten’s growth period is like a compressed version of human infancy through adolescence. Because their bodies develop so rapidly during the first year of life, even short-term weight fluctuations can signal health issues. If growth falls noticeably behind peers or weight stalls, it may be necessary to rule out parasitic infections, nutrient absorption problems, or congenital abnormalities. Conversely, gaining weight too quickly can lead to obesity or put undue stress on joints. That’s why the direction of the growth curve is more important than any single number.

Average Weight and Body Length Chart for Kittens by Month

Item	Average Weight	Average Body Length
1 month	400–500g	approx. 15–18cm (reference)
2 months	900g–1.1kg	approx. 20–23cm (reference)
3 months	1.3–1.7kg	approx. 24–27cm (reference)
4 months	1.8–2.3kg	approx. 27–30cm (reference)
6 months	2.5–3.2kg	approx. 32–36cm (reference)
9 months	3.2–4.0kg	approx. 36–40cm (reference)
12 months	3.5–4.5kg	approx. 38–42cm (reference)

These are rough averages based on Korean Shorthairs and mixed-breed cats. Up to about 6 months of age, you can track weight against a trend of roughly 0.45kg (1 pound) gained per month. However, there is significant variation by breed and individual, and the body length figures in particular are for reference rather than a standard benchmark. The direction (trend) of the growth curve matters far more than any single absolute figure, so for an accurate assessment, consult your veterinarian based on your pet's breed information.

Characteristics of Each Growth Stage

A kitten’s growth can be broadly divided into four stages.

Neonatal stage (0–2 weeks): The ear canals are closed, and kittens have difficulty regulating their body temperature. The eyelids typically begin to open around 10 days of age (range: 2–16 days). Kittens should gain weight steadily every day; any loss or stagnation in weight is a warning sign.

Socialization stage (2–8 weeks): Starting at 2 weeks of age, this is a critical period for socialization. Deciduous teeth erupt in sequence (incisors at 2–4 weeks, canines at 3–4 weeks, premolars at 5–6 weeks), and weaning begins. Hearing also approaches adult levels around 4–6 weeks of age.

Rapid growth stage (2–6 months): Body weight increases dramatically. A high-protein diet formulated specifically for kittens is essential.

Late growth stage (6–12 months): The rate of growth gradually slows, and puberty (first estrus or sexual maturity) may begin during this period. Since sexual maturity and behavioral development can continue until about 2 years of age, it is best to consult your veterinarian to determine the appropriate timing for spaying or neutering.

Illustrations of kittens growing through four stages by month of age

Growth Abnormality Signs Requiring Immediate Veterinary Attention

If your kitten’s weight drops within 24 hours or stalls for several days, that’s a warning sign. You should also check for congenital diseases or parasitic infections if the kitten is noticeably lighter than its littermates or has stopped growing. If the kitten eats well but doesn’t gain weight and has a pot-bellied appearance, intestinal parasites such as roundworms or coccidia may be the cause. If you notice any of these signs, don’t hesitate to visit a veterinary clinic for an examination that includes a fecal test.

Nutritional Management Points for the Growth Phase

Kittens require significantly more energy and nutrients per unit of body weight than adult cats. Feeding an inappropriate diet during this critical growth phase can lead to lifelong digestive and joint issues.

Protein: Kittens need a high-protein diet to support growth, and kitten-specific formulas are designed to meet these elevated protein requirements.

Fat: A higher fat content than that found in adult cat food is necessary to provide adequate energy density and facilitate the absorption of fat-soluble nutrients.

Calcium and Phosphorus Balance: To support proper skeletal development, choose a food that contains calcium and phosphorus in the appropriate ratio.

Feeding Frequency: Because young kittens have small digestive tracts, it is best to divide their daily food into multiple small meals. Gradually reduce the number of feedings as they grow.

Free-Choice vs. Scheduled Feeding: Free-choice feeding may benefit young kittens’ growth, but consult your veterinarian to adjust the feeding method as your kitten matures.

Always select a food specifically labeled for kittens.

Differences in Growth Rate by Breed

Even among cats of the same age, weight can vary significantly depending on the breed.

Small breeds: Small-breed cats such as Singapura and Munchkin have an adult body weight that is smaller than that of medium-breed cats. They may still be noticeably lighter than medium-breed cats at 12 months of age, so it is important not to mistake this for abnormal growth.

Medium breeds: Breeds like the Korean Shorthair and American Shorthair exhibit the most common body size range. The average values on growth charts are primarily based on this category.

Large breeds: Large-breed cats such as the Maine Coon, Norwegian Forest Cat, and Ragamuffin often continue growing even after 12 months of age. It can take several years to reach full maturity, and their final adult weight is significantly higher than that of medium-breed cats.

Checking the standard adult weight for your cat’s breed in advance through your veterinarian or breed-specific resources will help you assess their growth rate more accurately.

Tips for Measuring Weight

For the most accurate readings, weigh your kitten at the same time on the same day each week, before meals. If your kitten is too restless to stay still, you can hold them while stepping on the scale and then subtract your own weight. Consistently record the measurements in a notebook or app to chart their growth curve. The overall trend is far more informative than any single number.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

Is it okay if my kitten weighs less than average?

If your kitten’s growth curve is steadily trending upward, there’s no need to worry. However, if their weight is noticeably lower than that of kittens of the same age, or if their weight hasn’t increased for more than two weeks, it’s best to have them checked by a veterinarian.

How long should I feed my kitten kitten food?

We generally recommend feeding kitten food until your cat reaches 12 months of age. For large breeds such as Maine Coons and Norwegian Forest Cats, it is common to continue with kitten food until they are 18 to 24 months old.

They’re sibling kittens, but there’s a big difference in their weights.

Even among littermates, growth rates can vary from one puppy to another. Check the feeding environment to make sure the smaller puppy isn’t eating less or being outcompeted by its siblings.

At what weight in kilograms should a pet be spayed or neutered?

The decision is based on the cat's age and health status rather than weight. Since feline puberty typically begins between 6 and 12 months of age, it is best to consult with your veterinarian around this time to determine the appropriate course of action. Please always work with your veterinarian to decide on the specific timing and conditions for the surgery.

Is it okay to give milk to pets during their growth period?

Regular cow’s milk can cause diarrhea due to its lactose content. Use only kitten-specific formula (KMR), and after weaning, transition from formula to solid food.

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References

[1] Little, S.E., The Cat: Clinical Medicine and Management, Chapter 20 Pediatrics, 2012

[2] Case, L.P. et al., Canine and Feline Nutrition, Chapter 27 Feeding Growing Kittens, 3rd ed., 2011

[3] Hand, M.S. et al., Small Animal Clinical Nutrition, Chapter 16 Feeding Kittens, 5th ed., 2010