At what age is a Yorkshire Terrier considered an adult?

Most are considered physically mature by around 10 to 12 months, having reached close to their adult height much earlier, around 6 months. Full muscle tone and coat development can continue a little beyond that, but the major growing is done well within the first year.

How big should a Yorkshire Terrier be at 6 months?

Most puppies are close to their adult height by this age and roughly two-thirds to three-quarters of their expected adult weight, though this varies between individual dogs. If you have any concern about your puppy's growth, your vet can check it against a proper growth curve at a routine visit.

Why does my Yorkshire Terrier's coat keep changing colour?

This is normal. Yorkshire Terrier puppies are born darker and the coat gradually lightens and develops its adult tan-and-steel-blue pattern over the first year or so, sometimes continuing to shift slightly as the dog matures further.

Is it normal for a Yorkshire Terrier to stay very small?

Yes, the breed's whole standard is built around a small adult size, typically under 3.2kg, so a fully grown Yorkshire Terrier being noticeably smaller than most other dogs is entirely expected rather than a sign of a problem.

When is a Yorkshire Terrier fully grown?

Most Yorkshire Terriers reach roughly their adult height by around 6 months old, with weight and body condition continuing to fill out until somewhere between 8 and 12 months. As one of the smaller toy breeds, they mature faster than a large or giant breed, which can take up to two years to finish growing.

Reading a Yorkshire Terrier growth pattern

A Yorkshire Terrier puppy typically weighs well under a kilogram at birth and reaches its adult weight, usually somewhere between about 2 and 3.2kg for a healthy adult, faster than almost any other popular breed. Most of that growth happens in the first six months, with the remaining few months mostly filling out muscle and coat rather than adding meaningful height.

Individual dogs vary, and a Yorkshire Terrier's small adult size means differences of even a few hundred grams can look large as a percentage. A weight chart is a general guide, not a target — what matters more day to day is whether your puppy is growing at a steady, healthy rate rather than hitting a specific number by a specific week.

What actually finishes last

Coat texture is one of the slower things to settle in this breed. Yorkshire Terrier puppies are born with a soft, often darker puppy coat that gradually changes to the finer, silkier adult coat and characteristic tan-and-steel-blue colouring, a process that can continue well past the point where a dog has stopped growing physically.

Teeth also finish later than overall size might suggest, with adult teeth typically in by around six months, and toy breeds like the Yorkshire Terrier are more prone than most to retained baby teeth needing a vet's attention. Growth plates in the legs generally close by around 8 to 10 months in a breed this size, well before a larger breed's would.

Common questions

At what age is a Yorkshire Terrier considered an adult?: Most are considered physically mature by around 10 to 12 months, having reached close to their adult height much earlier, around 6 months. Full muscle tone and coat development can continue a little beyond that, but the major growing is done well within the first year.
How big should a Yorkshire Terrier be at 6 months?: Most puppies are close to their adult height by this age and roughly two-thirds to three-quarters of their expected adult weight, though this varies between individual dogs. If you have any concern about your puppy's growth, your vet can check it against a proper growth curve at a routine visit.
Why does my Yorkshire Terrier's coat keep changing colour?: This is normal. Yorkshire Terrier puppies are born darker and the coat gradually lightens and develops its adult tan-and-steel-blue pattern over the first year or so, sometimes continuing to shift slightly as the dog matures further.
Is it normal for a Yorkshire Terrier to stay very small?: Yes, the breed's whole standard is built around a small adult size, typically under 3.2kg, so a fully grown Yorkshire Terrier being noticeably smaller than most other dogs is entirely expected rather than a sign of a problem.

Sources

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.