The best an probably the easiest way to calculate exactly how many calories you need to gain weight you should take a look at a calorie calculator which you will find online. This will enable you to determine exact the amount of calories and grams of food required to bulk up, build muscle and generally gain good quality weight.
It is actually quite a simple calculation, which you can do yourself, but it needs specific parameters like your age, your gender, your current weight as well as your current height. In order to do it correctly you need to also include your daily activity level and how much you move around.
The problem with using the online weight gain calculator is that it obviously cannot take into account your current hormone level, the current speed of your metabolism, the function of your thyroid and many other factors which will have a huge difference on the speed at which you gain weight.
Everyone is different and there are no two people who will have exactly the same rate of metabolism because it varies all the time depending on many changing factors like stress for example. The issue with gaining good quality weight is to know where the weight is coming from that you are putting on.
Bodyweight will come from three different sources and they are simply fat, water or muscle. Obviously the most important consideration when looking at where your weight comes from is the kind of exercise that you do as well as your macro-nutrient levels.
Probably the most important consideration is your genes, and did you choose your parents correctly if you want to gain muscle fast? Because you can have two people exactly the same weight and height doing exactly the same diet and exercise and the one will gain 8 pounds of muscle a month and the other will gain one.
But there is absolutely nothing that you can do about the type of genes that you got from your family. The average person will gain a bit of fat along with gaining muscle mass so this is something that you need to watch. Because as you know your fat will hide any muscle gains that you get very well.
There is usually a danger of eating too many carbohydrates, which can result in fat gain. You need to be weary of this and try and be as specific as possible when working out your calories and the way that you combine your different food groups.
For more weight gain information go to Weight Gain Workout And Diet Plan