my baby weight is 7 kg and he is 8 months 26 days and his birth weight is 3.57kg is this normal ? what to keep for him to increase weight ?

A. If you look at the birth rate of your child your child should have been roughly around 7 1/2 to 8 kg by completing the time of six months because it is expected that the child should have two times of birth by the time of six months according to that