How much calories do i need to consume to gain weight healthily?

Difficult to Say: We need to know more to advise you. Are you male or female? Current weight? How tall are you? Are you very active or pretty inactive? Weight training? All of these & other factors come into play. Webmd and many other sites have calorie calculators that ask a variety of questions and can give a range for each day. Also note that the number will be an average per day.