Fitness calculator
Ideal Weight Calculator
Estimate ideal body weight using four clinical formulas and compare to the healthy BMI range.
Ideal weight (average of 4 formulas)
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How it works
These four formulas originated in clinical research for medication dosing and body surface area estimation. The Devine formula (1974) and subsequent refinements by Robinson, Miller, and Hamwi provide different estimates based on the observation that ideal body weight scales predictably with height for adults.
Each formula calculates a weight in kilograms using your height above 5 feet (60 inches). This calculator displays all four results and their average, as well as the broader healthy BMI weight range for your height.
The formulas apply to adults and ignore muscle mass, bone density, age, and frame size. Treat them as screening estimates rather than personal targets.
Worked example
Consider a 5'10" male (177.8 cm). Height above 5 feet is 10 inches.
Devine: 50 + (2.3 × 10) = 73.0 kg
Robinson: 52 + (1.9 × 10) = 71.0 kg
Miller: 56.2 + (1.41 × 10) = 70.3 kg
Hamwi: 48 + (2.7 × 10) = 75.0 kg
Average: (73.0 + 71.0 + 70.3 + 75.0) ÷ 4 = 72.3 kg
Healthy BMI range: 18.5 × (1.778 m)² to 24.9 × (1.778 m)² ≈ 58.5 to 78.7 kg
Which number should I trust?
The spread between the formulas is the most useful part of the answer. In the example above the four results span 70.3 to 75.0 kg, a range of nearly 5 kg (about 10 lb) for the same person. That spread is honest: no single number is the ideal weight for a given height.
The healthy BMI range of 18.5–24.9 is much broader and is evidence-based from large epidemiological studies. It acknowledges that many body compositions are healthy. A muscular person or athlete may exceed the upper BMI range without excess fat; an older adult with low muscle mass may be below it despite reasonable health.
Body composition matters more than scale weight: two people at the same weight can carry very different amounts of muscle and fat. To measure that side of the picture, use the body fat calculator, and use the BMI calculator to see where you sit in the healthy range.
Frequently asked questions
Why do the four formulas disagree?
Each formula came from a different study population and era. Devine (1974) was built for medication dosing; Robinson and Miller later re-fit the coefficients against other data. Predicting one weight from height alone carries real uncertainty, and the disagreement between formulas shows its size. The healthy BMI range expresses that uncertainty better than any single formula.
Is ideal weight different for athletes?
Yes. These formulas were developed for general adult populations and do not account for muscle mass. An athlete with high muscle density may weigh significantly more than the formula predicts yet have low body fat. If you are regularly strength training or have a muscular build, your actual 'ideal' weight will be higher than any of these formulas suggest. Focus on body composition and health markers, not the number alone.
Does age matter?
The formulas do not adjust for age, but age changes what a healthy weight looks like. Older adults lose muscle (sarcopenia), and some research finds slightly higher BMI ranges associated with better outcomes past 65. A healthcare provider who knows your history can weigh those factors; these formulas cannot.
This calculator is for informational and educational purposes only and is not medical advice. Its results are general estimates, not an individual assessment. Talk to a doctor, registered dietitian, or other qualified health professional before making decisions about your health, diet, or exercise.