The question "how much should I weigh" seems like it should have a simple answer, but the truth is that there is often not a straight forward answer to this question. One problem is that not all experts agree on what's considered healthy, and insurance companies also publish charts that are more about monetary risk than they are about real health (though there can be a correlation between the two). The other thing that makes it a tricky question is that everybody is different and a good weight for one person may not be a good weight for somebody else who appears to be similar.
Your best ally in determining your ideal weight is your doctor. They will be aware of your current health, as well as your medical history, each of which plays a role in figuring out what a good weight for you is. Not only can your doctor help you determine how much you should weigh, they can also give you suggestion for how to reach that weight.
If you spend any time trying to find out your ideal weight, you will find that just about every source will give you a slightly different answer. This makes it somewhat difficult to know how much you should weigh. You could always take an average weight of all sources, and try to factor in the various criteria they use to reach their recommendations. That will give you a fair idea of a good weight for you.
The Body Mass Index, or BMI, is one way that a lot of people use to get an idea of whether or not they are at a healthy weight. The Index uses a simple mathematical formula based on your height and weight to arrive at your number. The formula can be stated as kg/m^2, that is, your weight in kilograms divided by your height in meters, squared. Someone weighing 90 kilograms and 2 meters tall would have a BMI of 22.5 which is within the normal range. For the record, a BMI of 18.5 or less is considered underweight, 18.5 to 25 is normal, 25 to 30 is overweight, while anything above 30 is considered obese.
The BMI sounds good, and a lot of people do rely on it, but it does have one major flaw: it doesn't take into account the fact that muscle weighs more than same volume of fat. That means someone who is very muscular (such as a bodybuilder) can have an artificially high Body Mass Index.
So, while it would be wonderful if there was a single answer that fit everybody, the question of "how much should I weigh" is actually a more complicated question than it at first appears. That being said, there is a weight range that is ideal for you. With just a bit of sleuthing, and a visit to your personal doctor, you should be able to find out just what the best weight for you is.