What should be the average weight for 26 years old man with 5 feet 6 inch height?

128-156 pounds. The range is wide, as weight depends on body composition. If very athletic and muscular, the weight may be higher, as muscles weigh more than adipose tissue. Body mass index (bmi) is calculated by dividing weight in kilograms by height in meters squared. Overweight is defined as bmi of 25-30 kg/m2 and obesity is a bmi = or >30kg/m2.