The age of kittens is very important, both for socializing the kittens and also to know how to care for them.
Generally kittens are supposed to gain 4ozs. per week, but that does not always hold true. Many a kitten can weigh less for their age. What you need to look for are developmental milestones more so than weight, or size.
Alley Cat Allies (click here for their website), a national non-profit organization provides some good resources regarding kitten care and socialization. Click on the following links -
Caring for Neonatal Kittens
In depth information about caring for kittens can be found here - Hand Rearing Kittens.
THE REST OF THIS PAGE IS STILL UNDER CONSTRUCTION. WE WILL BE ADDING PICTURES TO HELP YOU WITH ESTIMATING KITTEN AGE.
Looked at the pictures below and still not sure about the age of your kitten? Additional pictures can be found on the Alley Cat Allies website, CLICK HERE.
Under one week: Eyes shut, ears flat to head, skin looks pinkish. Part of umbilical cord may still be attached. Weight < 4oz.
1 week-10 days: Eyes beginning to open, ears still flat. A kitten this age is smaller than your hand. 4 to 6oz weight.
2 weeks: Eyes open bright blue color, kittens will crawl a bit on their tummies, and basically just sleep and nurse. No teeth yet. 6 to 8oz. weight.
3 weeks: Eyes are fully open, ears are erect, teeth are becoming visible, may just be begining to come through the gums Kittens this age are just starting to walk and will be very wobbly. 8 to 12 oz weight.
4-5 weeks: Kittens have begun to pounce and leap. Kittens this age will begin to eat regular cat food, and will begin to use a litter box. They are still quite small at this age. they will weigh anywhere from 1/2 lb to 1 lb.
6-7 weeks Kittens are quite active and weigh about 1 pound to 1 an 1/2 pounds Their eye color, changes from blue to its permanent color. May still be friendly and approach people. Very playful at this stage.
8 weeks: Kittens this age weigh approximately 1 and 1/2 pounds to 2 pounds. If they have not been exposed to humans, they will likely be feral and unapproachable.
11-12 weeks (3 months).
12 months (1 year).