Hi , I have been working out of about 6months now and I have gained 14KG (90% or more muscle) and I stopped gaining now from the 4th month , its probably cuz i havent been eating more than i used to , but i wanna know if i have fast metabolism how many calories do i need a day ? because i think calories are my problem not protein cuz i get 120+g of protein every day ..
Your going to want to calculate your BMR. Basal metabolic rate. There is plenty of online calculators for that. After that you'll want to take that number and plug it into the Harris-Benedict equation.
That will give you your overall calories in a day. To gain weight simple add a few hundred calories to that number.