Can anyone please tell me what the " average " weight gain a puppy should be gaining each week. My baby will be 12 weeks old next week, and from 4 weeks to 8 weeks he gained 200 grams (7.05 ounces) every 2 weeks. From 8 to 10 weeks he gained 300 grams (10.58 ounces), and now from 10 to 12 weeks he has gained 350 grams (12.35 ounces). He now at 12 weeks is weighing 1300 grams (47.62 ounces or 2.97 pounds). Hes very active running all day playing and doesnt look so big but according to the "weight charts", he is going to be if he carries on at this rate.