Havanese dogs tend to be full-grown by the time they're 12 to 18 months of age. Several things contribute to when a puppy will mature. The most important factor is the puppy's bloodline. Ask about your puppy's parents to determine when he'll be full grown.
The average Havanese dog is 8 1/2 to 11 1/2 inches tall at the shoulder when full grown, according to the American Kennel Club breed standard. Some puppies who reach their mature height by 12 months of age may take longer to fill out to their adult body weight, which averages between 8 and 13 pounds. Some Havanese weigh sightly less than this; some more. At any rate, Havanese dogs are considered fully grown by their second birthday. You can be reasonably sure your puppy won't grow much more after his first birthday, though.
Your puppy's breeder is the best source for determining how and when your puppy will mature. The breeder will have records of his family's bloodlines. Ask to see your puppy's parents when you pick him up to see what he might look like as an adult. A puppy whose parents are on the large side will likely be the same. Ask your puppy's breeder how old his parents were when they stopped growing to get an approximation of when your puppy might mature. Your puppy's parents affect much more than his size. He gets his color, temperament and health from them too. Learning about a puppy's bloodlines will help you predict what he will be like.
Estimate how big your Havanese puppy will be by multiplying his weight at 8 weeks of age times 4. He is roughly one-quarter of his adult weight at that age. Double his weight at 16 weeks of age for a fresh estimate of his final size.
Breeders use this formula to estimate how much their puppies will ultimately weigh. The 16-week estimate is believed to be more accurate than one taken at 8 weeks, when most puppies are still in their litters.
The Havanese's coat makes your dog appear much bigger than he is. The breed is known for a small, sturdy body covered by a double coat of hair. Although both the inner and outer coats are silky and lightweight, they are fluffy and add bulk to the Havanese's appearance. The dog's outer coat, slightly heavier than the undercoat, helped to keep the dog cool in the tropical Cuban climate of the breed's origin.
Your Havanese puppy's coat will change between 8 and 15 months of age as his puppy coat is replaced by the adult coat. An adult Havanese's coat is usually between 6 and 10 inches long. Daily grooming is a must even if you have your dog trimmed.