Female cats typically give birth after 63 to 67 days of gestation, but some may go as long as 70 days. It is important to weigh kittens when they are born and at least every other day until they are 2 weeks old to ensure that they are healthy.
The average kitten weighs about 99 grams at birth. Most will weigh between 91 and 105 grams.
It isn't uncommon for kittens in small litters to weigh more or in very large litters to weigh less. Very tiny kittens may not survive. Less than 88 grams is considered low birth weight.
Kitten weight may depend on the breed. Maine coons, one of the largest house cat breeds, often weigh 125 to 136 grams.
It's important for kittens to maintain a steady increase in weight, veterinarian Mary D. McCauley says on the website of the Maine Coon Breeders and Fanciers Association. Stopping weight gain or loss of weight indicates a problem. 7 to 14 grams per day is normal.
Buy a scale that weighs in grams to accurately measure your kitten's weight.