height and of a labrador puppy

Question
what should be the average height and weight of a 6 to 7 months labrador puppy?

Answer
If I ever saw a figure from a reliable source, I don't remember.   They vary so much, that the average tells you nothing about any one dog.  Many of them, their rate of growth levels off at that age.  They may have 80-90% of their adult height.  Some continue rapid growth.  Try feeling the ends of his leg bones.  If they are still quite knobby, he will continue growing.  Once the growth plates close, they are no longer so large, and growth slows.  

Here is an interesting link, http://jn.nutrition.org/cgi/content/full/134/8/2027S

If you are still feeding a puppy chow now, switching to an adult chow for the larger breeds now slows growth and helps develop sturdier joints.

Your dog definitely should be narrower at the waist than the hips and chest. You should be able to easily feel the ribs, but not see them. Each dog is different. Standard recommendations are a good place to start, but each dog must have its food and exercise adjusted to its individual needs. Here is a link to a good illustrated guide, http://www.longliveyourdog.com/twoplus/RateYourDog.aspx