Ideal Weight Calculator

Why Multiple Formulas?

There's no single 'correct' ideal weight, which is why this calculator shows results from several established formulas rather than one number. Each was developed for a particular purpose and population. The Devine formula (1974) is used clinically, often for calculating medication doses based on body size, and is widely recognised in medicine. The Robinson and Miller formulas are refinements offering slightly different estimates. The Hamwi formula is a quick clinical rule of thumb. They broadly agree but can differ by several kilograms, because they're all simplified models based on height and sex that don't capture the full diversity of healthy human bodies. Seeing the range across formulas is more honest than a single figure, because it reflects that 'ideal weight' is genuinely a range, not a precise target. These formulas also share limitations: most were derived decades ago from specific populations, use only height and sex, and don't account for muscle mass, body frame, age, or body composition. A muscular athlete may weigh well above their 'ideal' yet be very healthy, while someone at their 'ideal' weight could have an unhealthy body composition. So treat the formula results as a rough reference point — a ballpark of what's typical for your height — rather than a goal to chase. A healthy weight range (such as the BMI healthy band) and good body composition matter more than matching any single formula's output.

Body Frame Size

Body frame size helps explain why two people of the same height can both be healthy at noticeably different weights. People with larger frames — broader shoulders, wider hips, thicker bones and joints — naturally carry more weight without excess fat, while small-framed people carry less. Standard ideal-weight formulas don't account for this, which is one reason they should be read as ranges rather than exact targets. A simple way to gauge frame size is wrist circumference relative to height: a larger wrist relative to height suggests a larger frame, a smaller wrist a smaller frame. Elbow breadth is another clinical indicator. As a rough adjustment, large-framed people sit toward the upper end of a healthy weight range (or slightly above formula estimates), and small-framed people toward the lower end. Frame size is set by your skeleton and can't be changed, so it's a legitimate reason your healthy weight differs from a formula's average. That said, frame estimates are themselves approximate, and it's easy to overestimate your frame to justify a higher weight — so use it as a modest adjustment, not a large exemption. The broader point is that 'ideal weight' formulas describe statistical averages for a height, and your healthy weight depends on your individual build, muscle, and composition. Frame size is one of several reasons the right weight for you is a personal range rather than a universal number.

The Practical Takeaway

Rather than chasing a single ideal-weight figure, the more useful approach for most people is to aim for the BMI healthy range (a Body Mass Index of 18.5 to 24.9), which gives a healthy weight band for your height rather than one number. This typically aligns reasonably with the various ideal-weight formulas while acknowledging that healthy weight is a range. But weight and BMI are screening tools, not the whole picture. BMI doesn't distinguish muscle from fat, so it can misclassify muscular people as overweight and can miss high body fat in those with low muscle. That's why it's worth looking beyond the scale: waist measurement (a marker of harmful abdominal fat), body composition, fitness, energy levels, and how you feel all matter, often more than a precise weight. For most people, the practical goals are staying within the healthy BMI range, keeping waist size in check, being physically active, and eating well — rather than fixating on hitting an exact 'ideal' kilogram figure that the formulas themselves disagree on. If you're significantly outside the healthy range, or have specific health concerns, a GP or dietitian can give personalised advice that accounts for your individual circumstances. Use this calculator's figures as a reference range to understand roughly what's typical for your height, then judge your health by the fuller picture rather than a single target weight.

Weight vs Wellness

Ideal body weight formulas calculate a statistical average, not a personal optimum. Your healthiest weight depends on body composition, age, genetics, fitness level, and individual health markers. Two people with identical height and weight can have very different health profiles. A more meaningful target than a specific number: a weight at which your blood pressure, blood glucose, and cholesterol are in healthy ranges, you have energy for daily activities, and you feel comfortable. Sustainable