Calculate your ideal body weight based on height and gender using multiple formulas. Free online.
IBW (men) = 48 + 2.7 × (H_in − 60) | IBW (women) = 45.5 + 2.2 × (H_in − 60)Hamwi (1964): 48 kg base for men, plus 2.7 kg per inch above 5 ft. 45.5 kg base for women, plus 2.2 kg per inch above 5 ft. H_in = height in inches. Robinson, Miller, and Devine formulas use slightly different constants.
Estimate your ideal body weight using four widely used medical formulas: Devine, Robinson, Miller, and Hamwi. Results differ slightly by formula — the range gives a realistic target, not a single rigid number.
All four formulas were originally designed for clinical dosing calculations (drug dosing by body weight), not fitness goals. Devine (1974) is the most widely cited. Robinson and Miller are variations. Hamwi is often used for quick bedside estimates. None of them account for body composition — a muscular athlete may weigh more than the "ideal" range while being perfectly healthy.
BMI classifies weight relative to height. Ideal weight formulas do the same but express the result as a weight range rather than an index. For most people, the "healthy BMI" range (18.5–24.9) and the ideal weight range will overlap closely.
These formulas don't account for age (muscle decreases with age), ethnicity, or body composition. A healthy weight for you depends on your muscle mass, bone density, and overall metabolic health — factors a single formula can't capture.
The calculator shows results using multiple formulas: Devine (most common in clinical settings), Hamwi, Robinson, and Miller. Each gives a slightly different result — the range across formulas is your practical target.
Ideal weight ranges are generally similar across adulthood but may allow a slightly higher range for older adults (over 65) since some additional weight is associated with better outcomes in that group.
Ideal Body Weight: What the Formulas Actually Say