The average litter size for a domestic cat is between two and six kittens, with three to four kittens being the most common litter size. However, litters of up to twelve kittens are not unheard of. The world record for the largest litter of domesticated cats was set in 1970, when a Siamese cat gave birth to nineteen kittens. The largest number of kittens born to a single domestic cat was twenty-seven, which occurred in 2002.
A female cat can have multiple litters during her lifetime. The number of litters she has will depend on several factors, such as how often she mates, whether she is spayed, and her overall health. A healthy unspayed female cat can have three or more litters per year. In contrast, a spayed female cat will only have one litter every one to two years (or none at all if she is retired from breeding).