How big will my Shih Tzu get?
A fully grown Shih Tzu typically weighs somewhere between about 4 and 7.5kg and stands roughly 20 to 28cm at the shoulder, though where your own dog lands in that range depends on its parents and individual build. Most reach close to their adult size by around nine to twelve months old.
What to expect as your Shih Tzu grows
As a small toy breed, a Shih Tzu's growth is far more gradual and predictable than a large or giant breed's rapid early growth spurt. Most of the growing happens in the first six to nine months, with smaller, slower changes in body shape and coat continuing up to around eighteen months.
Individual size varies more than owners often expect, even within the same litter, so a smaller or larger sibling growing up beside your dog is not unusual and does not necessarily mean either is outside a healthy range for the breed.
Reading a growth or weight chart
A breed weight chart gives a general range rather than a target for every individual dog, and a Shih Tzu's parents are often the better guide — a puppy from two smaller parents is more likely to stay on the smaller end of the range, and the reverse for larger parents.
Weighing your puppy every few weeks and plotting it gives a clearer picture of whether growth is steady than a single reading compared against a generic chart, and your vet can flag anything that looks like it is tracking unusually fast or slow at a routine check.
Common questions
- At what age is a Shih Tzu fully grown?
- Most Shih Tzus reach close to their adult height and weight by around nine to twelve months old, with some minor filling out in body shape continuing up to about eighteen months. Growth is gradual throughout, without the rapid early spurt seen in larger breeds.
- How much should a Shih Tzu weigh?
- Adult Shih Tzus typically weigh somewhere between about 4 and 7.5kg, though the exact healthy weight for your individual dog depends on their build and parentage. Your vet can advise on a healthy weight range at a routine check-up.
- Why is my Shih Tzu smaller than others in the litter?
- Size variation within a litter is normal, even for a small, consistent breed like the Shih Tzu. As long as your puppy is growing steadily and eating well, being on the smaller end of the range is not usually a concern on its own.
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Written against guidance published by UK veterinary and welfare organisations. Always confirm specifics with your own vet.
Written by Matt Garnett, who runs Giddy Pets and is a lifelong pet owner — not a vet. This is general information, not veterinary advice, and it cannot replace an examination by the vet who knows your animal. How we write these guides.