Thanks for writing to health care magic.
Normally babies triple their birth weight
by the age of 1 year and double by age of 5 to 6 months.
Only a growth chart
can tell if a baby is growing normally or not.
What diet you are giving to your baby?
They require a diet rich in proteins
and calories for their growth.
Most of the babies have recurrent episodes of viral infections before their immunity matures.
Hope this helps.