Ideal Weight Range Calculator
Calculate your ideal weight range from four validated formulas, and understand what each one measures.
No single formula gives a definitive ideal weight. Each was developed for a specific purpose with specific populations. I include all four here because seeing them together, and understanding that they produce a range rather than a single number, is more useful than picking one and treating it as gospel. The consensus zone where all four agree is the most defensible target.
Ideal weight formulas were developed for clinical use (drug dosing, BMI classification) rather than as personal fitness targets. They're reference points, not prescriptions. Body composition, muscle vs fat ratio, matters more than the number on a scale.
The four formulas
Hamwi (1964): For men: 106 lbs for the first 5 feet + 6 lbs per additional inch. For women: 100 lbs for the first 5 feet + 5 lbs per additional inch. ±10% gives a healthy range. Originally developed for clinical nutrition estimates. Devine (1974): For men: 50 kg + 2.3 kg per inch above 5 feet. For women: 45.5 kg + 2.3 kg per inch above 5 feet. Widely used in medicine for drug dosing calculations. Robinson (1983): Refinement of Devine. For men: 52 kg + 1.9 kg/inch above 5 feet. For women: 49 kg + 1.7 kg/inch above 5 feet. Miller (1983): For men: 56.2 kg + 1.41 kg/inch above 5 feet. For women: 53.1 kg + 1.36 kg/inch above 5 feet. These formulas were all developed for Western adult populations and may not generalize well across ethnicities.
BMI healthy weight range for reference
The BMI healthy range (18.5–24.9) translates to a specific weight range for each height. For a 5'10" person: 129–173 lbs. This range is wide and includes people with very different body compositions. Someone at 165 lbs with low body fat and significant muscle is very different from someone at 165 lbs with high body fat and low muscle, despite identical BMI.
Body composition vs weight
All weight-based formulas share the same limitation: they don't distinguish between muscle and fat. A 195-lb person who is 15% body fat has about 166 lbs of lean mass. A 175-lb person at 30% body fat has 122 lbs of lean mass. The first person is arguably healthier despite weighing more. Waist-to-height ratio, body fat percentage, and metabolic health markers (blood pressure, glucose, lipids) are more informative than any single weight target.
Frequently asked questions
Which formula should I use?
None definitively. Look at where the formulas agree, the overlap zone is the most defensible target. For most adults within normal height ranges, the formulas cluster within 5–10 lbs of each other. For very short or very tall individuals, the formulas diverge more, and BMI-based range may be more useful.
Should I try to hit my ideal weight?
Pursue health outcomes, not a number. Focus on body fat percentage, cardiovascular fitness, strength, blood markers, and energy levels. The scale is one data point. If you're metabolically healthy and fit, you may be at your ideal weight even if a formula disagrees.