I found some formulas based on height only (like Devine, Robinson, Miller), but I want to calculate the ideal weight based on gender, age and height.
Is it possible? If so, which formulas are there and how do I use them? Or are there other ways of determining the ideal weight?
There is no one ideal weight because beauty is in the eye of the beholder. Each person will give you a different formula. Even within one sport, there exist many different proposed formulas for ideal body weight. For example, this article shows the many different forumulas proposed by scientists and athletes within the sport of professional bodybuilding. The famous old-school bodybuilder Steve Reeves gives this formula:
Bodybuilding legend Steve Reeves presented simple formulas for calculating what he considered to be ideal muscular weight. He suggested starting with a base of 160 pounds and adding 5 pounds for every inch of height above 5'5". For people above 6'0", he suggested starting with 200 pounds and adding 10 pounds per inch. Using these formulae, a person 5'9" would have an ideal muscular weight of 180 pounds. A person 6'1" would weigh 210 pounds. The problem with these predictions is that they do not consider bone structure size.
The bodybuilders of today would give a different formula than Steve Reeves. They would lean towards a much heavier ideal weight because that's the current trend. The best thing you can do is to look at who you want to look like and follow their formula. Maybe it's Steve Reeves, maybe it's not. And if they don't have a published forumula, look at their current weight and height, then make estimated adjustments for your height.
Aesthetically there is no such thing, but a number of academics have proposed arbitrary formula that do incorporate those 3 variables: age, sex and height eg.
what you should really be looking for is an ideal weight range based on long term health e.g.
Below the range 22·5–25 kg/m2, BMI was associated inversely with overall mortality, mainly because of strong inverse associations with respiratory disease and lung cancer. These inverse associations were much stronger for smokers than for non-smokers, despite cigarette consumption per smoker varying little with BMI.
Anyway to answer your specific question, this may do:
