my grandson's birthweight was 3.940 kgs now after 1 month 10 days his weight is 5.2 kgs is it normal

A. Typically, a baby's weight doubles within their first 4 to 6 months of life and triples in their first year. For instance, a baby born weighing six pounds would typically weigh about 12 pounds by the time they were 6 months old and about 18 pounds by the time they turned 1. Slow weight gain is not always a concern.