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How to Calculate Ideal Weight
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"Ideal weight" refers to a weight range associated with good health for a given height. Several different formulas exist, each developed in a different context and with different trade-offs. None is perfect. They are best used as rough targets, not precise prescriptions.
Common Ideal Weight Formulas
G.J. Hamwi (1964) — used in clinical nutrition:
• Men: 48 kg (106 lbs) for first 5 feet + 2.7 kg (6 lbs) per inch above 5 feet
• Women: 45.5 kg (100 lbs) for first 5 feet + 2.2 kg (5 lbs) per inch above 5 feet
JD Robinson (1983):
• Men: 52 kg + 1.9 kg per inch above 5 feet
• Women: 49 kg + 1.7 kg per inch above 5 feet
BMI-based range: The weight that corresponds to a BMI of 18.5–24.9 for your height. This produces a wider range and is probably the most commonly cited method.
Why Results Differ Between Formulas
These formulas were created decades ago, often for clinical contexts (adjusting medication doses), not as general health guidelines. They do not account for muscle mass, bone density, age, or ethnicity. A muscular person may be above the formula's ideal weight while being extremely healthy; a sedentary person may fall within range while carrying unhealthy levels of body fat.
A More Useful Framing
Rather than targeting a specific number on the scale, focus on measurable health markers:
• Blood pressure within normal range (under 120/80)
• Fasting blood glucose under 100 mg/dL
• Healthy lipid panel
• Waist circumference below the high-risk threshold
• Feeling energetic and able to perform daily activities without difficulty
Weight is one input among many.
Try the Ideal Weight Calculator.
Frequently Asked Questions
Should I aim for the middle of the ideal weight range?
Not necessarily. Any weight within the healthy range is acceptable. Athletes and muscular individuals often perform best at the higher end of the range or slightly above.
Is it healthy to be at the lower end of the "normal" BMI range?
Generally yes, as long as it is maintained through adequate nutrition and not restriction. Very low weight (BMI under 18.5) is associated with nutritional deficiencies, bone loss, and other health issues.