The average amount of weight for a baby is 150g p/wk for 0-3mths; 100g 3-6mths and then 60-80g for 6-12mths. These are only averages and there will be some who just stack it on and others who just poke along. The same can be said for both methods of infant feeding too. According to the new WHO growth chart that I have he is just above the 15th centile, but keep in mind too that he has put on a huge amount of weight in five months and thats a pretty great effort! Plus he is probably a lot more active now and burning up some of what he puts on kwim?

Either way he sounds just perfect to me