How old is my kitten?
For the first two months, weight is one of the best clues. Healthy kittens gain about 7 to 15 grams (roughly a quarter to half an ounce) every day, so each week has a fairly predictable range. This kitten age calculator compares your kitten’s weight against the week-by-week ranges in the ASPCA kitten chart and gives the matching age.
Combine the number with what you can see. A kitten whose weight says “two weeks” but whose eyes are still sealed shut is probably younger and small, not older.
Kitten weight chart by week
Normal weight ranges from the ASPCA kitten progression chart:
| Age | Normal weight |
|---|---|
| Birth | 70–115 g (2.5–4 oz) |
| 1 week | 142–190 g (5–6.7 oz) |
| 2 weeks | 191–295 g (6.7–10.4 oz) |
| 3 weeks | 240–400 g (8.5–14.1 oz) |
| 4 weeks | 289–505 g (10.2–17.8 oz) |
| 5 weeks | 338–610 g (11.9–21.5 oz) |
| 6 weeks | 387–715 g (13.7–25.2 oz) |
| 7 weeks | 436–820 g (15.4–28.9 oz) |
| 8 weeks | 485–925 g (17.1–32.6 oz) |
After eight weeks, a common rule of thumb is that kittens weigh about 1 lb per month of age until five or six months old. Breed and sex make a difference, so treat older-kitten estimates as rough.
Signs of age, week by week
From Alley Cat Allies’ guide to kitten ages:
- Under 1 week: eyes shut, ears folded down, can’t walk. The umbilical cord may still be attached.
- 1 to 2 weeks: eyes start to open (they’re blue), ears begin to unfold, crawling.
- 3 weeks: eyes and ears fully open, first wobbly steps, baby teeth starting to come in, reacting to sounds.
- 4 to 5 weeks: eye colour starts to change from blue, running and pouncing, weaning onto soft food, starting to use a litter box.
- 8 weeks: about 2 lb and looking like a miniature cat.
An example: you find a kitten weighing 12 oz (about 340 g) whose eyes are open and who’s taking unsteady steps. The weight alone fits anywhere from about 2 to 5 weeks, but open eyes and first wobbly steps point to around 3 weeks. That kitten is too young to eat solid food alone and needs kitten milk replacer, warmth and frequent feeds.
Found a kitten? What to do first
- Wait and watch from a distance if the kitten looks healthy. The mother is often nearby and comes back.
- Keep it warm before anything else. Young kittens can’t control their own temperature.
- Never give cow’s milk. Use kitten milk replacer from a pet store or vet.
- Weigh it daily on a kitchen scale. Steady gain is the best sign things are going well.
- See a vet soon, especially if the kitten is cold, weak, not eating or losing weight.
Common questions
How much should a kitten weigh at 8 weeks?
Usually somewhere around 485 to 925 g (about 1 to 2 lb), according to the ASPCA chart. Many shelters wait until about 2 lb before spay or neuter surgery.
How much weight should a kitten gain a day?
About 7 to 15 g a day in the first weeks. A kitten that doesn’t gain, or loses weight, needs a vet quickly.
How can I tell a kitten’s age by its teeth?
Baby teeth start coming in around three weeks, and adult teeth replace them from about three to six months. A vet can judge age from teeth fairly well.
When can kittens eat solid food?
Weaning usually starts around four to five weeks with soft, wet kitten food, alongside milk.
How old is my kitten in human years?
A kitten ages fast. By its first birthday it’s about 15 in human terms. Try the cat age calculator.
Sources
Last reviewed .