my 2 month old son not gaining weight properly he's current weight 3 kg and he is breastfeed and formula I give both

A. Namaste Mom Monthly weight gain is expected in range 400 gm to 1 kg and by age of 4 to 6 months they almost double their birth weight the quantity should be about 100 to 125 ml per feed about 5 to 6 times a day