Ideal Body Weight Calculator

No single formula is universally the most accurate. The Devine formula is the most widely used in clinical medicine, particularly for drug dosing. However, research comparing all four formulas to measured body composition data shows that averaging them produces a more reliable estimate than relying on any one alone. This calculator shows all four results so you can see the range.

Each formula was developed using different population data, at different times, and for different purposes. Devine based his formula on drug dosing charts, Robinson refined Metropolitan Life insurance tables, Miller used a broader dataset, and Hamwi developed his for quick dietetic assessments. The differences are usually small (within 2 to 5 kg) and reflect the natural uncertainty in defining one ideal weight for a given height.

No. All four IBW formulas use only height and sex as inputs. They do not account for muscle mass, body fat percentage, or body composition. A muscular person will almost certainly weigh more than their calculated IBW while being perfectly healthy. If you train with weights regularly, your IBW should be treated as a lower bound rather than a target.

The simplest method is to measure your wrist circumference with a tape measure. For men: under 6.5 inches is small, 6.5 to 7.5 inches is medium, and over 7.5 inches is large. For women: under 6 inches is small, 6 to 6.25 inches is medium, and over 6.25 inches is large. You can also wrap your thumb and middle finger around your wrist: if they overlap you have a small frame, if they touch you have a medium frame, and if there is a gap you have a large frame.

Not necessarily. Your ideal body weight is a clinical estimate based on population averages. Your goal weight should be personalised to your body composition, training history, lifestyle, and health markers. Many people set a goal weight that is higher than their IBW because they carry more muscle mass, and that is perfectly appropriate. Use IBW as a reference point, not a rigid target.

The IBW formulas themselves do not include age as a variable, so the calculated number stays the same regardless of your age. However, body composition naturally shifts with age: muscle mass tends to decrease and fat mass tends to increase. Some health professionals suggest that a slightly higher body weight in older adults (BMI 25 to 27) may actually be protective against frailty and muscle wasting.

Athletes can use IBW formulas as a general reference, but they should not use them as targets. Most athletes, particularly those involved in strength sports, bodybuilding, or sports requiring significant muscle mass, will weigh well above their calculated IBW. For athletes, body fat percentage and sport-specific performance metrics are far more useful measures than ideal body weight.