Kitten Weight Chart by Week — Complete Growth Guide (Birth to 6 Months)
Weekly kitten weight chart from birth to 6 months, with milestone ages, feeding amounts, failure-to-thrive red flags, and when to use KMR milk replacer.
Week-by-week kitten weight chart
| Age | Weight (g) | Weight (oz) | Milestone |
|---|---|---|---|
| Birth (Day 0) | 85-110g | 3-4 oz | Eyes closed; nurse every 1-2h |
| Week 1 | 150-200g | 5-7 oz | Umbilical cord falls off |
| Week 2 | 200-300g | 7-10 oz | Eyes open; ear canals open |
| Week 3 | 280-400g | 10-14 oz | First teeth; starts walking |
| Week 4 | 380-500g | 13-17 oz | Introduce gruel (wet food + KMR) |
| Week 5 | 460-650g | 1.0-1.4 lb | Litter box training begins |
| Week 6 | 550-800g | 1.2-1.8 lb | Eating mostly solid food |
| Week 8 | 800-1000g | 1.8-2.2 lb | Fully weaned; vaccinate FVRCP |
| Week 12 (3 months) | 1.0-1.5 kg | 2.2-3.3 lb | Second FVRCP; play boundaries |
| Week 16 (4 months) | 1.5-2.0 kg | 3.3-4.4 lb | Final FVRCP + rabies; spay/neuter discussion |
| 6 months | 2.3-3.5 kg | 5-7.7 lb | Spay/neuter window |
| 9 months | 3.0-4.5 kg | 6.6-10 lb | Near adult size (DSH) |
| 12 months | 3.5-5.5 kg | 7.7-12 lb | Full adult size (most breeds) |
Growth rate (what to track daily)
Weekly weight gain is less sensitive than daily weight trend. Weigh newborn kittens every 24 hours with a kitchen scale (1-gram resolution). Expected:
- Week 1-2: gain 10-15g per day
- Week 3-4: gain 15-20g per day
- Week 5-8: gain 20-30g per day
- Week 9+: transition to weekly weighing
Weight plateau for 24h (no gain) in kittens under 4 weeks = veterinary emergency. This can indicate fading kitten syndrome, hypoglycemia, dehydration, or congenital issues.
When to supplement with KMR
Kitten Milk Replacer (KMR) is formulated to match queen's milk. Use it when:
- Queen died, rejected kitten, or has mastitis
- Large litter (>5 kittens) — competition for nipples
- Kitten isolated (runt)
- Weight gain < 10g/day
- First-time mother with inadequate milk
Never use cow's milk — it causes severe diarrhea and dehydration in kittens. Lactose content is too high.
Feeding schedule by age:
- 0-1 week: 2 mL per feeding, every 2 hours (12 feedings/day)
- 1-2 weeks: 5-10 mL, every 3 hours (8 feedings)
- 2-3 weeks: 10-15 mL, every 4 hours (6 feedings)
- 3-4 weeks: 15-20 mL, 4 feedings; introduce gruel
- 4-6 weeks: gruel dominant; KMR 2-3 times/day
- 6-8 weeks: solid food; KMR optional
Red flags
- No weight gain for 24 hours (under 4 weeks) — emergency
- Weight loss of more than 5% — emergency
- Pale gums — anemia (parasites, FeLV, dehydration)
- Cold kitten — hypothermia shortens life; warm gently with heating pad under towel
- Distended belly — GI obstruction, fluid, or severe worm load
- Pot-belly + poor coat + growth lag — classic roundworm signs; deworm ASAP
Frequently Asked Questions
How much should a newborn kitten weigh?
Newborn kittens weigh 85-110g (3-4 oz) at birth. Lower than 80g is considered low birth weight and needs extra attention — supplementation with KMR is often needed for survival. Weight should double by 2 weeks and triple by 4 weeks.
How fast should kittens gain weight?
Healthy kittens gain 10-15g per day (0.35-0.5 oz). That's 70-100g per week. Weight plateau or loss for 24 hours in a kitten under 4 weeks is a VETERINARY EMERGENCY — fading kitten syndrome can kill within 48 hours.
What should my kitten weigh at 8 weeks?
By 8 weeks (the age most kittens go to new homes), they should weigh 800-1000g (1.8-2.2 lb). Smaller purebreds (Devon Rex, Singapura) can be 700g; larger breeds (Maine Coon, Ragdoll) 1100+g.
When do kittens stop growing?
Most domestic shorthair kittens reach adult size by 10-12 months (8-12 lb). Large-breed cats (Maine Coon, Ragdoll, Savannah) continue growing until 3-4 years, eventually reaching 15-25 lb.
Why is my kitten underweight?
Common causes: poor milk supply from queen (supplement with KMR), parasites (roundworms nearly universal in kittens), upper respiratory infection (decreased appetite), congenital defects (cleft palate, PKD). ALL underweight kittens need vet evaluation under 8 weeks old.
When should I transition to solid food?
Introduce wet kitten food mixed with KMR at 4 weeks (gruel consistency). Gradually reduce KMR by week 6. Fully weaned by 8 weeks. Never rush — kittens weaned too early develop digestive and behavioral problems.
Is my kitten too fat?
Rare in kittens — they burn calories fast for growth. An overweight kitten (BCS 7+) usually means over-feeding calorie-dense wet food without portion control. Kitten obesity doubles the risk of adult diabetes. Switch to measured meals, not free-feeding.
How much should my kitten eat?
Kitten food packaging gives guidelines by age/weight — start there. Typical: 2-month-old kitten eats 3 oz wet food + 1/4 cup kitten kibble daily (mixed feeding). Young kittens need 4 meals/day; reduce to 3 at 4 months, 2 at 6 months.
Sources & References
- [1]Cornell Feline Health Center: Kitten Development — Cornell University College of Veterinary Medicine
- [2]AAFP: Feline Life Stage Guidelines — American Association of Feline Practitioners (2021)
- [3]Merck Veterinary Manual: Nutrition in Kittens — Merck Veterinary Manual