Weigh and measure yourself. Once you know your exact height and weight, refer to a weight chart. A woman who is 5 feet 6 inches tall and between 26 and 59 years old should ideally weigh between 136 and 164 lb. The standard weight for a man who stands at 5 feet 9 inches is between 142 and 176 lb. For each inch you are shorter, subtract around 3 lb. from both ends of the range; for each inch you are taller, add 3 lb. Weight calculators and health websites will help you narrow these numbers down even more. The Centers for Disease Control has weight assessments on its website (see Reference section).
Determine your frame size by measuring your wrist. The smaller the diameter, the smaller your bones are. Smaller bones are usually less dense and therefore lighter. Consider your frame size because it can affect your measurements; a person with a large frame might mistakenly think she’s overweight. For an approximate idea, if you wrap your thumb and index finger around your opposite wrist, you can estimate your frame size. If your fingers overlap, you have a small frame; if they barely touch, you have a medium frame; if they don't touch, you have a large frame.
Compare your weight with your age group. Age becomes a factor with weight because with age comes a slowed metabolism, and caloric requirements drop. If a 26-year-old man is used to eating 2,200 calories a day and continues to do so for the next 20 years, he will gain weight.
Talk to your doctor about your ideal weight. He will be able to provide a more precise depiction of your overall health. He can also help you take steps to increase or decrease your weight as necessary to make sure you stay healthy.