How Big Is A Maine Coon Kitten: The Facts

How Big Is A Maine Coon Kitten - studio image of four grey and black tabby maine coon kittens sitting lined up together

by Dr. WL Wilkins, DVM, PhD.

Maine Coon cats are well-known for their large size, often being one of the biggest domesticated cats you can have. From kittenhood to adulthood, their weight and size can be astonishing.

But even these “gentle giants” start off as kittens – are these kittens also giants? How big is a Maine Coon kitten exactly?

Let’s jump into the facts and find out!

How Big Is A Maine Coon Kitten At Birth?

If you think that a big cat like the Maine Coon would have bigger than average kittens compared to most other domestic cat breeds, you’d be right!

Published studies report an average birth weight of 115-120 grams (1, 2). Although this sounds small, that is up to 50% bigger than the average birth weight of a Persian kitten, which is reported to be 82 grams.

This is just the average birth weight, meaning that approximately half of Maine Coon kittens will be born weighing more than 115-120 grams. Kittens have been known to be as large as 182 grams when born (3).

Factors Impacting Newborn Maine Coon Kitten Weight

Besides breed influence, individual kitten sizes can vary based on things like the number of kittens in the litter, the health and genetics of the parents, and the specific lineage of the breed.

Litter Size in Maine Coons

  • Typical Range: Maine Coon cats generally average 5 kittens per litter.  However, it’s not uncommon for a litter to have 6 or more kittens.
  • Factors Influencing Litter Size: The litter size can be influenced by the mother’s age, health, and genetic factors. Younger and first-time mothers tend to have smaller litters.

Size Variations Within a Litter

  • Genetic Diversity: Even within a single litter, kittens can inherit different combinations of genes from their parents. This genetic lottery can result in noticeable size variations among siblings.
  • Nutrition and Health of the Mother: The health and diet of the mother cat during pregnancy directly impact the development and size of the kittens. A well-nourished and healthy mother is more likely to have a litter of robust, evenly-sized kittens.
  • Intrauterine Growth: The position of each kitten in the uterus can affect its access to nutrients, thus influencing its size at birth.

Influence of Litter Size on Individual Kitten Size

  • Nutritional Competition: In larger litters, there’s more competition for nutrition both before and after birth. This competition can impact the size of each kitten.
  • Smaller Litters Leading to Larger Kittens: When a litter is small, the available nutrients from the mother are divided among fewer kittens, both in utero and during nursing. This can result in larger individual kittens, as each one receives a greater share of the resources.
  • Room to Grow: There is limited room inside the uterus, so when there are many kittens in a litter they have less room to grow while in the womb.

The Phenomenon of “Runts”

  • Definition: The “runt” of the litter is the smallest kitten, often significantly smaller than its siblings.
  • Causes: Runts may have experienced inadequate nutrition in utero, possibly due to a less favorable position in the womb. They might also have underlying health issues or genetic factors that result in smaller size.
  • Outcomes: With proper care, runts can usually catch up in size and health to their littermates. However, they often require extra attention in their early weeks.

And of course, the size of the mother also impacts the birth weight of the kittens. Bigger mothers tend to produce bigger kittens, while smaller mothers may have smaller kittens.

How Big Is A Maine Coon Kitten - small grey maine coon kitten learning to walk
How Big Is A Maine Coon Kitten 123rf

Maine Coon Kitten Size At One Month

Maine Coon kittens grow a lot in the first month of their lives. By the time they reach 1 month old, these kittens on average weigh around half a kilogram (over 1 pound), which is a substantial size for kittens of this age.

Weight Differences Between Male and Female Kittens

  • Male Maine Coon Kittens: On average, a male Maine Coon kitten will weigh about 558 grams at 4 weeks of age. This slightly higher weight compared to their female counterparts is an early indicator of the sexual dimorphism (size difference between sexes) common in this breed.
  • Female Maine Coon Kittens: Female kittens tend to weigh a bit less, with an average weight of around 530 grams at the same age.

Growth and Development at One Month

This rapid growth in the first month is a precursor to the overall large size Maine Coons are known for as adults.

Maine Coon Kitten Size At Three Months

By the time Maine Coon kittens reach three months of age, their growth is even more noticeable. At three months, Maine Coon kittens typically weigh almost 2 kilograms (over 4 pounds).

Males at this age are noticeably larger than their female counterparts. The average weight for a male Maine Coon kitten at three months is around 1985 grams, compared to an average of 1772 grams for females (1).

At this stage, their weights are significantly higher than many other cat breeds. For context, a male Persian kitten of the same age typically weighs around 1350 grams (3 pounds).

Developmental Milestones

  • Physical Development: At three months, Maine Coon kittens are much more active and coordinated. Their play is more complex, and they exhibit a greater range of cat behaviors.
  • Social Development: This age is also a critical time for social development. Maine Coon kittens are learning important social cues from their littermates, mother, and human handlers.
  • Dietary Needs: At three months kittens should be weaned and on solid food. Their dietary needs are substantial due to their rapid growth. As they transition off mother’s milk and onto solid food, they should be getting high-quality kitten food designed for large breeds.

The size of Maine Coon kittens at three months is a pretty good indicator of their potential size as adults. Kittens that are larger than average for the breed tend also to be larger than average as adults.

How Big Is A Maine Coon Kitten - four fat fluffy grey tabby maine coon kittens sitting lined up, studio image

Growth After Three Months

Unlike many other cat breeds, Maine Coons continue growing for several years. They don’t reach their full size until they are around 3 to 5 years old.

After three months, their growth rate remains steady but slows down compared to the initial three months. The growth is both in terms of weight and physical size, including their distinctive long and bushy tails, large paws, and tufted ears.

Once fully grown, male Maine Coons usually weigh between 15 to 25 lbs (7 to 11 kg), while females are generally smaller, weighing between 8 to 12 pounds (3.6 to 5.4 kg) on average.

They can reach up to 40 inches (102 cm) long when measured from nose to tail tip. They are also tall, with a height that can range between 10 to 16 inches (25 to 40 cm) at the shoulder.

Even though they won’t reach their full size until 3 to 5 years, they usually reach their adult proportions and physical characteristics by about one year of age.

Despite reaching their full adult size much later than other cat breeds, Maine Coons do not live longer than the average cat. Like other breeds, their average lifespan is between 12 and 15 years.

How Big Is A Maine Coon Kitten - 3 month old grey tabby maine coon kitten laying on a white countertop


Maine Coon kittens grow A LOT from birth through the first few months of life!

At birth, they average between 115 to 120 grams, already showing a larger size compared to many other breeds. By one month, this rapid growth continues, with kittens typically weighing around half a kilogram, over 1 pound, with male kittens slightly heavier than females.

At three months, their growth is significantly outpacing the growth rates of many other cat breeds.  This growth continues until they are about 3 to 5 years old, when they reach their full size.

Not all Maine Coons will grow up to be true giants in the cat breed, but they will almost always be larger than most other cats!  Their size and rapid growth make for an exciting journey to watch as a kitten owner.

So if you’re considering adding a Maine Coon kitten to your family, be sure to prepare for their fast-paced growth.

[Editor’s Note: Want to learn more about Maine Coon cats? Check out our complete Maine Coon Breed Information and Care Guide!]


  1. Birth weight and postnatal growth of pure-bred kittens
  2. Obstetric and newborn parameters in the Maine Coon cats
  3. Birth weight in the feline species: Description and factors of variation in a large population of purebred kittens
  4. A pilot study of the body weight of pure-bred client-owned adult cats


  • Dr. Wendy Wilkins DVM PhD.

    Dr. Wendy Wilkins is an experienced veterinarian and epidemiologist with over 20 years of expertise. She holds a Doctor of Veterinary Medicine (DVM) degree and a Doctorate in Epidemiology from the University of Saskatchewan. Throughout her career, Dr. Wilkins has excelled in clinical practice, academia, research, and regulatory veterinary medicine. She is a respected voice in knowledge dissemination, delivering factual information in a readable and understandable manner through articles, books, and public engagements.

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