Last updated: October 3, 2026
Kitten Growth & Development
Kitten Growth Chart: From Newborn to Adulthood
Track your kitten's growth with weekly weight milestones, learn about developmental stages, temperature requirements, and when kittens reach full size.
Quick Answer
Kittens gain roughly 1 lb per month for the first 6 months, so a kitten's age in months is close to its weight in pounds. Most reach their adult size by 12 months, while large breeds like Maine Coons keep growing until 18 to 24 months. For target weights by breed, see our Kitten Growth Chart by Breed. Find your kitten's week in the milestones table below, estimate adult size with our Kitten Weight Calculator, see how big your cat will get, and set daily food with the Kitten Calorie Calculator.
Kitten Growth Milestones
Weekly weight expectations and developmental stages from birth to adulthood
| Age | Weight Range | Developmental Stage |
|---|---|---|
| 2 weeks | 0.25-0.5 lbs | Eyes open, beginning to crawl |
| 4 weeks | 0.5-1 lbs | Starting to walk, beginning to play |
| 6 weeks | 1-1.5 lbs | Weaning begins, very playful |
| 8 weeks | 1.5-2 lbs | Fully weaned, ready for adoption |
| 12 weeks | 2-3 lbs | Rapid growth phase |
| 16 weeks | 3-4 lbs | Teenage phase, high energy |
| 20 weeks | 4-5 lbs | Approaching adult size |
| 24 weeks | 5-6 lbs | Nearly full grown |
| 52 weeks | Adult weight | Fully grown adult cat |
Note on the ranges: These are typical figures for average domestic and mixed breed cats, where a healthy adult usually lands around 8 to 11 lbs (3.6 to 5.4 kg). Large breeds are different. A Maine Coon, Ragdoll, or Norwegian Forest Cat keeps growing well past 12 months and often weighs 12 to 20 lbs (5.4 to 9 kg) at maturity, so a kitten from one of these breeds will sit above the numbers above at every age. For target weights tied to your kitten's breed, see our Kitten Growth Chart by Breed.
How Fast Do Kittens Grow?
The first six months are a sprint, then growth slows to a crawl
Kittens grow faster in their first half year than at any other point in their lives. A useful rule of thumb is that a healthy kitten gains about 1 pound (roughly 0.45 kg) per month for the first six months, which means a kitten's age in months is a close guess at its weight in pounds. A 3 month old kitten is often near 3 lbs, a 4 month old near 4 lbs, and so on.
Weight gain is steepest between 8 and 16 weeks, then tapers as the kitten approaches adult size. By 6 months, most cats have reached about 75 percent of their adult weight, and the last quarter fills in slowly over the following months. You can see where your kitten should land next month with our Kitten Growth Calculator, or check a specific age against typical figures on our 6 month old cat guide.
Newborn Kitten Weight & Care
Critical first weeks of life
Birth Weight
Newborn kittens typically weigh 3-4 ounces (85-115 grams) at birth, with a healthy range of 2.5-5 ounces (70-140 grams). Healthy kittens should double their birth weight in the first week. If a kitten is not gaining weight or weighs less than 2.5 ounces at birth, consult your veterinarian immediately.
First Week Growth
During the first week, kittens should gain approximately 0.25-0.5 ounces (7-14 grams) per day. By 1 week old, kittens typically weigh 4-8 ounces. If a kitten is not gaining weight or is losing weight, this may indicate health issues, feeding problems, or the need for supplemental feeding.
Temperature Requirements
Newborn kittens (0-2 weeks) cannot regulate their body temperature and need an ambient temperature of 85-90°F (29-32°C). Use heating pads set on low, warm blankets, or a heat lamp to maintain proper temperature. By 2-4 weeks, they need 80-85°F (27-29°C), and after 4 weeks, room temperature (70-75°F) is acceptable.
When to Be Concerned
Consult your veterinarian immediately if: your kitten is not gaining weight, losing weight, crying excessively, not nursing, or appears weak or lethargic. Early intervention is crucial for newborn kitten health. Keep a weight log to track growth and share with your veterinarian.
Kitten Growth Phases
Understanding developmental stages
Early Growth (2-8 weeks)
Kittens grow rapidly during this phase, gaining weight steadily each week. By 8 weeks, kittens typically weigh 1.5-2 pounds and are fully weaned. This is when kittens are typically ready for adoption. During this phase, kittens learn to walk, play, and explore their environment.
Rapid Growth (8-16 weeks)
This is the most rapid growth phase. Kittens gain approximately 0.5-1 pound per month during this period. By 16 weeks (4 months), kittens typically weigh 3-4 pounds and are in their "teenage" phase with high energy levels. Proper nutrition is crucial during this phase.
Approaching Adulthood (16-24 weeks)
Growth begins to slow as kittens approach adult size. By 20 weeks (5 months), kittens typically weigh 4-5 pounds and are approaching adult size. By 24 weeks (6 months), most kittens weigh 5-6 pounds and are nearly full grown, reaching about 75% of their adult weight.
Reaching Full Size (24-52 weeks)
Most kittens reach their full adult size by 52 weeks (12 months). However, large breed cats like Maine Coons may continue growing until 18-24 months. During this final growth phase, kittens gain the remaining 25% of their adult weight and develop adult muscle mass.
When Do Kittens Stop Growing?
Most cats finish around their first birthday, but not all
For the average domestic cat, growth in height and length is mostly done by 12 months, with a little filling out of muscle and body condition continuing to around 18 months. This is why a cat is usually considered an adult at one year old and switched from kitten food to adult food around that time.
Large and slow maturing breeds are the exception. Maine Coons, Ragdolls, Norwegian Forest Cats, and Savannahs commonly keep adding size until 18 to 24 months, and some Maine Coons are still broadening their frame at three years. If you have one of these breeds, do not worry that your kitten looks lanky at a year old, that is normal. To estimate your cat's final adult size from its current weight, use our how big will my cat get guide, and compare figures across ages on our cat weight by age chart.
Kitten Growth by Breed Size
Small, medium, and large breeds follow different curves
Small breeds
Breeds like the Singapura, Devon Rex, and Cornish Rex mature to roughly 5 to 8 lbs (2.3 to 3.6 kg). They tend to finish growing a little earlier and sit below the average milestone weights at each age.
Medium breeds
Most domestic shorthairs, Siamese, and British Shorthairs land around 8 to 12 lbs (3.6 to 5.4 kg) as adults. These are the cats the standard milestone table above fits best.
Large breeds
Maine Coons, Ragdolls, and Norwegian Forest Cats reach 12 to 20 lbs (5.4 to 9 kg) and keep growing past 12 months. Expect them to track above the average ranges at every stage.
For weight targets matched to a specific breed, see our Kitten Growth Chart by Breed.
What Affects How Big a Kitten Gets
Genetics set the ceiling, but care shapes the result
Genetics and breed
The single biggest factor. A kitten's breed and the size of its parents set the range it can reach. Sex matters too, as males usually grow larger and heavier than females of the same breed.
Nutrition
Growing kittens need calorie dense food made for growth, fed several times a day. Underfeeding stunts growth, while overfeeding adds fat rather than frame. Our kitten feeding guide covers how much and how often.
Health and parasites
Worms, illness, and early weaning can all slow growth. A kitten kept on a steady deworming and vaccination schedule, with any illness treated promptly, has the best chance of reaching its full potential size.
Spay and neuter timing
Spaying or neutering does not stunt a cat and does not make it fat on its own. It slightly lowers calorie needs, so portions may need trimming afterward, but it has little effect on final skeletal size when nutrition stays appropriate.
Kitten Temperature Requirements
Proper temperature management is crucial for newborn kitten survival
Newborn Kittens (0-2 weeks)
Temperature: 85-90°F (29-32°C) ambient temperature required. Newborn kittens cannot regulate their body temperature and rely on their mother and environment for warmth. Use heating pads set on low, warm blankets, or a heat lamp to maintain proper temperature.
2-4 Weeks Old
Temperature: 80-85°F (27-29°C) ambient temperature. Kittens begin to develop some ability to regulate temperature but still need supplemental heat. Gradually reduce heating as they age.
4+ Weeks Old
Temperature: Room temperature (70-75°F / 21-24°C) is acceptable. Kittens can now regulate their body temperature effectively. Ensure they have warm bedding and shelter from drafts.
Important: Always monitor kittens for signs of hypothermia (cold to touch, lethargic, not nursing) or hyperthermia (panting, restlessness). If you suspect temperature-related issues, consult your veterinarian immediately.
Is My Kitten a Healthy Weight?
The scale is only half the picture, feel counts too
Because kittens vary so much by breed, the number on the scale is best read alongside how your kitten actually looks and feels. Vets use a body condition score for this. On a healthy kitten you should be able to feel the ribs easily under a thin layer of fat, see a slight waist when looking down from above, and notice a gentle tuck of the belly from the side.
If the ribs are hard to find, or there is no waist, the kitten may be carrying too much weight. If the ribs, spine, and hips stick out sharply, it may be underweight and worth a vet visit. Learn how to score your cat step by step in our cat body condition score guide, and check current weight against age norms with the Kitten Weight Calculator.
How to Weigh a Kitten at Home
A kitchen scale and a weekly routine are all you need
Small kittens are easiest to weigh on a digital kitchen scale that reads in grams or fractions of an ounce, since a bathroom scale is not sensitive enough for a one pound kitten. Place a small towel or bowl on the scale, press tare to reset it to zero, then set the kitten in and read the number. For a wriggly kitten, weigh yourself holding it and then alone, and subtract.
Weigh at the same time of day, ideally before a meal, and record each result in a simple log or in the Kitten Growth Calculator. Weekly checks for the first few months are ideal. Steady gains are what you want to see, and any week of weight loss in a young kitten is a reason to call your vet.
Tracking Your Kitten's Growth
Tools and tips for monitoring healthy development
Weekly Weighing
Weigh your kitten weekly during their first few months using a kitchen scale or pet scale. Record weights in a log to track growth trends. Healthy kittens should gain weight steadily. If weight gain stalls or decreases, consult your veterinarian.
Using Growth Calculators
Our Kitten Weight Calculator compares your kitten's current weight to expected ranges for their age and predicts adult size. Our Kitten Growth Calculator shows future milestones based on current age and weight. Both tools help ensure your kitten is growing at a healthy rate.
Nutrition for Growth
Kittens need 2-3x more calories per pound than adult cats due to rapid growth. Use our Kitten Calorie Calculator to determine appropriate daily calorie intake. Feed high-quality kitten food formulated for growth, and ensure kittens eat 3-4 times per day until 6 months old.
When to Consult a Veterinarian
Consult your veterinarian if: your kitten is not gaining weight, losing weight, not eating, appears weak or lethargic, or is significantly outside expected weight ranges. Early intervention is crucial for kitten health. Bring your growth log to veterinary appointments.
Frequently Asked Questions About Kitten Growth
Common questions about kitten weight, growth milestones, and development
How much should a newborn kitten weigh?
Newborn kittens typically weigh 3-4 ounces (85-115 grams) at birth, with a range of 2.5-5 ounces (70-140 grams). Healthy kittens should double their birth weight in the first week. If a kitten is not gaining weight or is losing weight, consult your veterinarian immediately.
What is a healthy kitten weight by age?
Healthy kitten weights vary by age: 2 weeks (0.25-0.5 lbs), 4 weeks (0.5-1 lbs), 6 weeks (1-1.5 lbs), 8 weeks (1.5-2 lbs), 12 weeks (2-3 lbs), 16 weeks (3-4 lbs), 20 weeks (4-5 lbs), and 24 weeks (5-6 lbs). By 52 weeks (1 year), kittens reach their adult weight. Use our Kitten Weight Calculator to track your kitten's growth.
When do kittens reach full size?
Most kittens reach their full adult size by 12 months (52 weeks). However, large breed cats like Maine Coons may continue growing until 18-24 months. Kittens grow most rapidly in their first 6 months, reaching about 75% of adult size by 6 months. Use our Kitten Growth Calculator to track milestones.
What temperature should newborn kittens be kept at?
Newborn kittens (0-2 weeks) need an ambient temperature of 85-90°F (29-32°C) as they cannot regulate their body temperature. By 2-4 weeks, they need 80-85°F (27-29°C). After 4 weeks, room temperature (70-75°F / 21-24°C) is acceptable. Use heating pads or warm blankets to maintain proper temperature.
How often should I weigh my kitten?
Kittens should be weighed weekly during their first few months to monitor growth. Healthy kittens should gain weight steadily. If your kitten is losing weight or not gaining, consult your veterinarian immediately. Use our Kitten Weight Calculator to track growth and compare to expected ranges.
What if my kitten is underweight?
If your kitten is underweight, consult your veterinarian immediately. Underweight kittens may have health issues, parasites, or feeding problems that need to be addressed. Your vet can help create a plan for healthy weight gain. Use our Kitten Calorie Calculator to ensure adequate nutrition.
What if my kitten is overweight?
While kittens need adequate nutrition for growth, being overweight can lead to health problems. However, never restrict food without veterinary guidance, as kittens need proper nutrition for development. Consult your veterinarian if concerned about your kitten's weight. Use our Kitten Calorie Calculator to ensure appropriate calorie intake.
How can I track my kitten's growth?
Weigh your kitten weekly and compare to growth milestones. Use our Kitten Weight Calculator to track current weight against expected ranges and predict adult size. Our Kitten Growth Calculator shows future milestones based on current age and weight. Keep a growth log to share with your veterinarian.
How fast do kittens grow?
Kittens grow fastest in their first six months, gaining roughly 1 pound (about 0.45 kg) per month. A handy rule of thumb is that a kitten's age in months is close to its weight in pounds, so a 4 month old kitten is often near 4 lbs. Growth is steepest between 8 and 16 weeks, and by 6 months most cats have reached about 75 percent of their adult weight.
Do all kitten breeds grow to the same size?
No. Small breeds like the Devon Rex mature to around 5-8 lbs (2.3-3.6 kg), medium breeds and most domestic shorthairs land near 8-12 lbs (3.6-5.4 kg), and large breeds such as Maine Coons, Ragdolls, and Norwegian Forest Cats reach 12-20 lbs (5.4-9 kg). Large breeds also keep growing past 12 months. See our Kitten Growth Chart by Breed for weight targets matched to your kitten's breed.
Does spaying or neutering stunt a kitten's growth?
No. Spaying or neutering does not stunt a cat or make it overweight on its own. It slightly lowers calorie needs, so portions may need trimming afterward, but it has little effect on final skeletal size as long as nutrition stays appropriate. Follow your veterinarian's advice on timing and adjust food using our Kitten Calorie Calculator.
Track Your Kitten's Growth
Use our free calculators to monitor your kitten's growth and ensure healthy development.
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