Kittens typically gain 100g weekly in their first 4 months, reaching 3.3–5 lbs (1.5–2.3 kg) at 4 months and 4.0–6.0 lbs (1.8–2.7 kg) at 5 months, then 4.6–7.0 lbs (2.1–3.2 kg) at 6 months. Use this kitten weight chart by month for benchmarks—weights vary by breed, but consistent weekly tracking helps you catch a stall or weight loss early, which matters most in very young kittens.
What Is a Normal Kitten Weight Chart by Month?
A normal kitten weight chart shows mixed-breed kittens starting at 3.5–4.5 oz (100–130g) at birth, doubling by week 2 to 7–9 oz (200–250g), reaching 1–1.5 lbs (450–680g) by month 1, 2.5–4.0 lbs (1.1–1.8 kg) by month 3, 3.3–5.0 lbs (1.5–2.3 kg) by month 4, 4.0–6.0 lbs (1.8–2.7 kg) by month 5, and 4.6–7.0 lbs (2.1–3.2 kg) by month 6. Rapid early growth slows after month 3; factors like diet, genetics, and health influence ranges. Vets also use a chart like this together with a body condition check, covered below.
| Age (Weeks/Months) | Average Weight (lbs/kg) | Weekly Gain Expectations | Key Notes |
|---|---|---|---|
| Birth (0 weeks) | 0.22–0.28 lbs / 0.1–0.13 kg | 10–15g daily | Very fragile; warm environment essential |
| Week 1 | 0.25–0.38 lbs / 0.11–0.17 kg | 100g/week | Doubling birth weight by end |
| Week 4 (1 month) | 1.0–1.5 lbs / 0.45–0.68 kg | 100g/week | Eyes open; breed variations start (Maine Coon +20%) |
| 12 weeks (3 months) | 2.5–4.0 lbs / 1.1–1.8 kg | 100g/week | Playful stage; steady gains |
| 16 weeks (4 months) | 3.3–5.0 lbs / 1.5–2.3 kg | 75–100g/week | Teething ends |
| 20 weeks (5 months) | 4.0–6.0 lbs / 1.8–2.7 kg | 50–75g/week | Muscle development |
| 24 weeks (6 months) | 4.6–7.0 lbs / 2.1–3.2 kg | 25–50g/week | Near adult frame |
| 52 weeks (12 months) | 8.0–11.0 lbs / 3.5–5.0 kg | Gains level off | Adult size for most breeds; large breeds keep filling out |
Weigh daily for newborns using a kitchen scale with a towel; track in a notebook or phone app for trends. A digital kitchen scale or a pet scale works for the first months. Deviations signal health issues.
How Much Should a Newborn Kitten Weigh Week by Week?
Newborn kittens weigh 3.5–4.5 oz (100–130g) at birth, 4–6 oz (110–170g) by week 1, 7–9 oz (200–250g) by week 2, 9–12 oz (250–340g) by week 3, and 1–1.5 lbs (450–680g) by week 4. Expect 10–15g daily gains; under 10g daily flags risks like fading kitten syndrome.
For accurate weighing, use a digital kitchen scale lined with a soft towel at the same time daily. Record weights in a notebook or app to spot stalls early; a stall in an under-4-week kitten needs a call to your vet the same day, because hypothermia and infection can develop fast.
What Weight Milestones Mark Healthy Kitten Growth?
Healthy milestones include 1.0–1.5 lbs (0.45–0.7 kg) at month 1 (eyes open, walking), 2.5–4.0 lbs (1.1–1.8 kg) at month 3 (peak play), 3.3–5.0 lbs (1.5–2.3 kg) at 4 months (teething ends), 4.0–6.0 lbs (1.8–2.7 kg) at 5 months (muscle gain), and 4.6–7.0 lbs (2.1–3.2 kg) at 6 months (adult frame emerging). Growth curves steeply first 3 months, then steady.
How Much Do Kittens Grow From 7 to 12 Months?
After 6 months, weekly gains get smaller and growth shifts from height and length toward muscle. Your kitten will look like a small adult but will keep filling out through the chest and shoulders. Spay or neuter usually happens somewhere in this window, and energy needs drop afterward, so portions often need trimming to keep gains lean. Feed a food labeled complete and balanced for growth until your vet says to switch; the Cornell Feline Health Center feeding guide and the ASPCA general cat care guide both explain how needs change by life stage.
By 12 months, most domestic shorthairs land around 8–11 lbs (3.5–5.0 kg). Females and naturally small-framed cats often finish lighter, and large breeds such as Maine Coons keep growing well past their first birthday. Keep weighing monthly through this stage. A kitten that stops gaining for several weeks before reaching adult size, or suddenly jumps well above its usual curve, is worth a vet check.
Do Male and Female Kittens Grow at the Same Rate?
Males usually run a little heavier than females from the first weeks, and the gap widens as they grow. By 3 months, a male kitten may weigh around 1.3–1.8 kg (2.9–4.0 lbs), while a female of the same age often sits closer to 1.1–1.6 kg (2.4–3.5 lbs). Compare your kitten against its own sex and breed where you can, and focus on a steady upward trend rather than hitting one exact number.
How Do You Check Your Kitten's Body Condition Score?
The scale tells you how much your kitten weighs, but body condition score (BCS) tells you whether that weight is healthy for its frame. Vets use a 9-point scale, and a score of 4–5 out of 9 is ideal; the Association for Pet Obesity Prevention BCS charts show what each score looks like, and our tabby cat BCS chart covers the same scale. You can check it at home by sight and touch:
| Body Condition | What You See | What You Feel |
|---|---|---|
| Underweight | Ribs, spine, and hip bones stand out; no fat cover | Bones feel sharp with almost no padding |
| Ideal (4–5/9) | Visible waist from above; slight tummy tuck from the side | Ribs easy to feel under a thin layer of fat with light pressure |
| Overweight | No waistline; rounded potbelly | Ribs hard to find under fat |
Run your fingers gently along the chest once a week when you weigh your kitten. A kitten that sits below the chart range with prominent ribs needs a vet visit, while one well above the range with no waist needs portion control and more play. Checking BCS alongside the numbers helps you tell a big-boned kitten from one that is carrying extra fat.
Why Does Consistent Weighing Matter for Fading Kitten Syndrome?
Consistent weighing helps catch fading kitten syndrome, a serious and sometimes fatal condition in newborn kittens causing sudden weight loss, dehydration, or gains under 10g a day from infection, parasites, or hypothermia. Daily weigh-ins in the first weeks are the simplest way to notice a problem early, and any kitten that loses weight or fails to gain should see a vet the same day.
Can a Litter Box Camera Help When Tracking Kitten Growth?
A litter box camera does not replace the scale. LitterLens does not measure weight or body condition. It logs each visit and how long it lasts, stool shape and colour from images, and urine clump events, and after about 7 days it builds a baseline for each cat and flags changes from it. For a growing kitten, that history sits next to your weekly weights: if a kitten is gaining slowly and also has loose stool or fewer visits, you have specifics to share with your vet. It is informational only, and your vet confirms any diagnosis.
Check the fit before buying. LitterLens needs a flat surface and a litter box larger than L size (over 50×38 cm), which is bigger than many kitten boxes; see our kitten litter box size guide for sizes by age. The free tier includes live view, recording, and visit count and duration data. Abnormal stool alerts and analysis need a Care+ subscription.
How Can You Track Kitten Weight Trends in Multi-Cat Homes?
In multi-cat homes, label kittens for scale weighing and write each weight next to its name so litter mates do not get mixed up. If you also use a camera, multi-cat health monitoring cameras such as LitterLens can recognize individual cats and keep a separate visit history for each, which helps when you need to know which kitten had the loose stool. Recognition is best in homes with a few cats and is not perfect, so treat it as a lead to confirm by watching.
| Method | What It Tells You | Limits | How Often |
|---|---|---|---|
| Kitchen or pet scale | Exact weight and weekly gain | Time-intensive; hard to weigh several kittens at once | Daily in the first month, then weekly |
| Vet weigh-in | Calibrated weight plus a professional body condition score | Only at visits | Every vaccine and deworming visit |
| Litter box camera log | Per-cat visits, time in the box, stool shape and colour, urine clumps | Does not measure weight; cannot diagnose | Review weekly next to your weigh-ins |
When Should You Worry About Kitten Weight and See a Vet?
Worry if kitten is more than 10–20% below the range for its age, gains nothing in 48 hours, or shows lethargy, low appetite, or litter changes. Persians may be lighter, Bengals heavier—use as baselines. Portions and meal timing matter too, so check our guide on how often to feed a 3-month-old kitten. Note any diarrhea, straining, or changes in how often your kitten poops and pees and tell your vet.
What Tools Help You Track Kitten Growth at Home?
A digital scale, a notebook or phone note for weights, and a weekly hands-on body condition check give you the core picture of growth. A litter box camera adds a record of bathroom habits, and a behavior camera such as PawTrack lets you watch play and rest when you are away. Neither camera weighs your kitten, so keep the scale routine going and bring your logs to each vet visit.
FAQs About Kitten Weight
How much should a 3-month-old kitten weigh?
About 2.5–4.0 lbs (1.1–1.8 kg). Males often sit toward the top of that range and females toward the bottom.
How much should a 4-month kitten weigh?
3.3–5.0 lbs (1.5–2.3 kg) on average. Weigh weekly and call your vet if there is a stall of more than a couple of weeks.
How much should a 5 month old kitten weigh?
About 4.0–6.0 lbs (1.8–2.7 kg). Gains slow to roughly 50–75g a week as muscle develops.
How much should a 6 month old kitten weigh?
About 4.6–7.0 lbs (2.1–3.2 kg). Your kitten is near its adult frame and gains only 25–50g a week.
How much should a kitten weigh at 1 year?
Most domestic shorthairs reach about 8–11 lbs (3.5–5.0 kg) by 12 months. Small-framed cats may finish lighter, and large breeds keep growing into their second year.
What causes fading kitten syndrome weight loss?
Dehydration, infection, parasites, and chilling. A kitten that loses weight needs a vet the same day.
Does LitterLens work for kittens?
Partly. In a compatible litter box (larger than L size), it logs visits, time in the box, stool and urine clump events, and builds a baseline in about 7 days. It does not measure weight, so you still need a scale.
How often should I weigh my kitten?
Daily first month, weekly after; log in a notebook or app for trends and vet sharing.
Are these weights breed-specific?
No. They are averages for mixed breeds. Ask your vet about Maine Coon, Sphynx and other breed variations.
Conclusion: Using the Kitten Weight Chart
Use this kitten weight chart by month as your baseline. Weigh on a schedule, check body condition by hand, and keep a written log. Call your vet if your kitten loses weight, stops gaining, or shows lethargy, low appetite, diarrhea or straining. Bringing your weight log and any litter box notes to each visit gives your vet the best picture of how your kitten is growing.
