Kitten Growth Chart: Weight, Age & Development Guide

Kitten growth happens fast, especially in the first few months, and tracking it is one of the simplest ways to catch a problem early. This guide is based on the AAFP Feline Life Stage Guidelines and standard feline pediatric references (see the full list at the end).

There’s no single “correct” weight line. Healthy ranges shift with breed, genetics, and nutrition. Track growth trends rather than focusing on any single weight. Body Condition Score matters as much as weight itself: a kitten within the expected range for its age can still be under- or overweight depending on how that weight is distributed.

Weight by Age: Birth to 12 Weeks (Rapid Growth Phase)

This is the fastest-growing period of a cat’s life. Healthy neonates should gain weight consistently every day; failure to gain over 24–48 hours deserves prompt veterinary attention.

Weights shown in kilograms (kg). Multiply by 2.2 for pounds.

Age	Average weight	Weight (lbs)	Daily gain
Birth	90–130 g	0.2–0.3 lbs	~0 (baseline)
1 week	150–250 g	0.3–0.6 lbs	7–14 g
2 weeks	250–350 g	0.6–0.8 lbs	10–14 g
3 weeks	350–450 g	0.8–1.0 lbs	10–14 g
4 weeks	450–550 g	1.0–1.2 lbs	10–14 g
6 weeks	650–750 g	1.4–1.7 lbs	7–10 g
8 weeks	750–950 g	1.7–2.1 lbs	7–10 g
10 weeks	~1.0–1.1 kg	2.2–2.5 lbs	5–8 g
12 weeks	~1.2–1.4 kg	2.6–3.0 lbs	5–8 g

Clinical tip: the 7–14 g/day rule

Figures above are typical ranges for domestic cats, not validated breed-specific standards.
The 7–14 g rule: healthy kittens typically gain about 7–14 grams per day during the first few weeks of life. Failure to gain weight over 24–48 hours, or any persistent weight loss, should prompt immediate veterinary evaluation. Neonates can decline rapidly.

Weight by Age: 3 to 12 Months (By Breed Size)

Breed size matters enormously here. A 6-month-old Maine Coon can weigh nearly double a Singapura of the same age. Both are perfectly healthy.

Weights shown in kilograms (kg). Multiply by 2.2 for pounds.

Age	Small breed	Medium breed	Large breed
3 months	~1.0–1.2 kg	~1.2–1.5 kg	~1.5–2.0 kg
4 months	~1.4–1.7 kg	~1.7–2.1 kg	~2.1–2.8 kg
5 months	~1.7–2.1 kg	~2.1–2.7 kg	~2.7–3.5 kg
6 months	~2.0–2.5 kg	~2.5–3.2 kg	~3.5–4.5 kg
8 months	~2.3–2.8 kg	~2.8–3.8 kg	~4.0–5.5 kg
10 months	~2.5–3.0 kg	~3.2–4.2 kg	~4.5–6.5 kg
12 months	~2.6–3.4 kg	~3.5–5.0 kg	~5.0–7.0 kg
Adult (full)	2.5–3.5 kg	3.5–5.5 kg	5.5–9.0 kg+

One exception to remember: Maine Coons, Ragdolls, Norwegian Forest Cats, and Siberians don’t hit full size at 12 months. They can keep growing until 18–24 months. Many veterinarians recommend continuing a complete, growth-formulated kitten diet until these breeds reach skeletal maturity.

Development Timeline: What Happens When

Age	Milestone	Clinical notes
Days 1–3	Nursing established	Should gain weight every single day; any loss is a red flag
Days 7–14	Eyes open	Eyes open 7–14 days; ears open 10–14 days; still fully dependent on mother
Weeks 3–4	First steps & deciduous teeth erupt	Begins walking; litter box instinct starts; milk teeth emerge around day 21
Weeks 4–8	Socialization window	Critical period for human bonding. Gentle daily handling shapes lifelong temperament
Weeks 6–8	Weaning complete	Transition from gruel to wet food; mother's milk antibodies waning — parasite screening important
Weeks 6–8	First FVRCP vaccine	Core vaccine series begins (rhinotracheitis, calicivirus, panleukopenia)
Weeks 8–12	Adoption-ready age	Socialization nearly complete; immune system more capable; booster vaccines due
12 weeks	Rabies vaccine	First rabies vaccine; legal requirement varies by location
4–6 months	Sexual maturity possible	Queens can cycle as early as 4 months — spay/neuter before first heat strongly recommended
5–6 months	Permanent teeth fully erupted	Deciduous teeth replaced by adult dentition by ~6 months
6 months	~75% of adult weight	Rapid growth phase concluding; body composition shifting
10–12 months	Full size (most breeds)	Skeletal growth complete for small/medium breeds
18–24 months	Full size (large breeds)	Maine Coon, Ragdoll, Norwegian Forest Cat continue filling out through second year

The socialization window (approximately 2–9 weeks) deserves extra attention
This is arguably the single most important stretch of a cat’s behavioral life. Gentle, positive daily handling during this period is associated with more confident, sociable adult cats. Experiences during this window can have lifelong effects, and socialization attempted later is generally less effective, though not without value. If you’re fostering or working with a rescue, this is the window where your time matters most.

Fading kitten syndrome
A term for the sudden decline and death of a neonate, usually in the first two weeks, not one disease, but the endpoint of several (hypothermia, hypoglycemia, infection, congenital defects, poor nursing). A kitten who’s cold, limp, crying persistently, or not nursing effectively needs emergency care immediately, not a wait-and-see approach.

Feeding by Age

Kittens need far more calories, protein, and fat per kilogram than adults do. Feeding a complete, balanced kitten diet supports healthy growth, neurological development, and immune function during this rapid growth phase.

Age	Diet	Frequency	Notes
0–3 weeks	Mother's milk or kitten milk replacer (KMR)	Every 2 hours (neonates)	Never use cow's milk — causes diarrhea; KMR only if orphaned
3–4 weeks	Gruel: KMR + wet kitten food	4–6x per day	Offer from shallow dish; mother continues nursing
4–6 weeks	Wet kitten food (primary)	4–5x per day	Gruel ratio shifts toward solid food progressively
6–8 weeks	Wet + dry kitten food	3–4x per day	Introduce dry food alongside wet; ensure fresh water always available
2–6 months	High-quality kitten diet	3x per day	High protein (>30% DM), adequate DHA for brain development
6–12 months	Kitten diet continuing	2–3x per day	Do not switch to adult food until 12 months (large breeds: 18–24 months)

Don’t switch to adult food before 12 months (18–24 months for large breeds). If hand-rearing, use a commercial kitten milk replacer (KMR) only. Cow’s milk is nutritionally inadequate for kittens and commonly causes gastrointestinal upset. Two nutrients worth knowing by name: taurine, a sulfur-containing amino acid cats cannot synthesize in adequate amounts. Deficiency causes heart disease and blindness, and DHA, essential for brain and retinal development in young kittens.

Tracking Weight

Weight loss is often one of the earliest measurable indicators of illness, especially in neonates.

• 0–4 weeks: weigh daily, same time each morning
• 4–12 weeks: weigh every 2–3 days
• 3–12 months: weigh weekly or at vet visits

Use a gram-accurate kitchen scale for anything under a kilogram. Bathroom scales aren’t precise enough. A kitten gaining steadily, even below the midpoint of a range, is healthier than one whose weight is erratic.

Warning Signs That Need a Vet

Warning sign	Possible cause — see a vet
No weight gain for 24–48 hours (neonates)	Failure to thrive, inadequate nursing, congenital defect
Any weight loss at any age	Infection, parasites, intestinal disease, inadequate nutrition
Weight significantly below breed range	Parasitism, malnutrition, congenital disease, fading kitten syndrome
Bloated abdomen with poor growth	Roundworm or hookworm burden (extremely common in kittens)
Eyes not open by 2 weeks	Possible eye infection (ophthalmia neonatorum) — clean gently and consult vet
Persistent crying, cold to touch	Hypothermia or hypoglycemia — emergency in neonates
Diarrhea during weaning	Dietary transition, parasites, or feline panleukopenia — stool check recommended

A Few Things Worth Knowing on Their Own

The “1 pound per month” rule. A kitten’s weight in pounds roughly matches its age in months is a handy field estimate for guessing a stray’s age, but it only holds up to about 5 months, assumes a medium breed, and estimates age, not health. Use the breed-size tables above for anything that actually matters.
Parasites are a common, overlooked cause of poor growth. Roundworms and hookworms are extremely common in kittens and can stall weight gain even in kittens eating normally. Expect a fecal exam at the first vet visit. Standard preventive practice starts deworming around 2–3 weeks of age and repeats every two weeks until a kitten transitions to regular parasite prevention. Your vet will tailor your schedule. Fleas are worth taking seriously too. Even a moderate flea burden can cause dangerous anemia in very young kittens.
Early spay/neuter (before 5–6 months) doesn’t stunt growth. Current AAFP guidance supports pediatric spay/neuter as safe. Early-neutered males may end up fractionally taller due to delayed growth-plate closure. It’s not a health concern, and spaying before the first heat substantially lowers lifetime mammary tumor risk. Large-breed kittens are the one group worth a specific timing conversation with your vet.

References: AAFP/AAHA Feline Life Stage Guidelines (2021); AAFP Feline Behavior Guidelines; WSAVA Global Nutrition Guidelines; Merck Veterinary Manual (current edition); BSAVA Manual of Canine and Feline Reproduction and Neonatology; Little, August’s Consultations in Feline Internal Medicine; Sparkes et al., JFMS (2015). Always consult your veterinarian for guidance specific to your kitten.

Frequently Asked Questions