All are different.
The standard for Yorkies is not to exceed 7lbs but that's usually not always the case due to many different factors.
Jackson was 5lbs at 9 weeks old, 6lbs at 12 weeks, 8.6lbs at 16 weeks, and stayed at around 12lbs until about 1 year old. Now at 1.5 years old, according to the vets scale, he's 16lbs. I love my big boy!