This calculator uses four well-known Ideal Body Weight (IBW) formulas to estimate a healthy weight range based on your height and gender. These formulas are commonly used in clinical settings for medication dosing and nutritional assessments.
Formulas used
All formulas are based on height in inches over 5 feet (60 inches). For people under 5 feet, the base weight is used.
Formula
Male (kg)
Female (kg)
Hamwi (1964)
48 + 2.7 × inches over 5ft
45.5 + 2.2 × inches over 5ft
Devine (1974)
50 + 2.3 × inches over 5ft
45.5 + 2.3 × inches over 5ft
Robinson (1983)
52 + 1.9 × inches over 5ft
49 + 1.7 × inches over 5ft
Miller (1983)
56.2 + 1.41 × inches over 5ft
53.1 + 1.36 × inches over 5ft
Example: Male, 175 cm (5′9″)
Height in inches over 5ft = 9 inches
Hamwi: 48 + 2.7 × 9 = 72.3 kg
Devine: 50 + 2.3 × 9 = 70.7 kg
Robinson: 52 + 1.9 × 9 = 69.1 kg
Miller: 56.2 + 1.41 × 9 = 68.9 kg
Limitations of IBW formulas
Formulas were developed in the 1960s–1980s on specific populations
Do not account for age, muscle mass, ethnicity, or body composition
Athletes may have higher healthy weights due to muscle mass
BMI and body fat % provide complementary information
References
Hamwi GJ (1964). "Therapy: changing dietary concepts." American Diabetes Association.
Devine BJ (1974). "Gentamicin therapy." Drug Intell Clin Pharm 8:650–655.
Robinson JD et al. (1983). "Determination of ideal body weight." Am J Hosp Pharm 40:1016–1019.
Miller DR et al. (1983). "Calculations of ideal body weight." Am J Hosp Pharm 40:1258–1260.
What Is Ideal Body Weight and How Is It Calculated?
Ideal body weight (IBW) formulas were developed in the 1960s–70s primarily for calculating medication doses in clinical settings — not as personal fitness targets. The most widely used is the Devine formula (1974): for men, 50 kg plus 2.3 kg per inch over 5 feet; for women, 45.5 kg plus 2.3 kg per inch over 5 feet. Other formulas include Hamwi, Robinson, and Miller, which produce slightly different values for the same height.
These formulas give a single number, but a more useful frame is the healthy weight range corresponding to a BMI of 18.5–24.9. For someone 5'8" (173 cm), that's 125–168 lbs (57–76 kg) — a 43-pound range that accommodates natural variation in frame size, muscle mass, and body composition.
The formulas have known limitations: they don't account for muscle mass (athletes weigh more than "ideal" despite being in excellent health), frame size (a large-framed person has heavier bones), age (muscle loss with age affects optimal weight), or ethnicity (some populations have different body fat distributions at the same BMI).
A Better Approach: Healthy Weight vs. Ideal Weight
Rather than chasing a single number, focus on these evidence-based targets: BMI 18.5–24.9 (associated with lowest all-cause mortality for most populations). Waist circumference below 40 inches (men) or 35 inches (women), which predicts cardiovascular risk better than BMI alone. Body fat percentage in the fitness or acceptable range for your age and sex.
Equally important are functional health markers: resting heart rate (50–70 bpm is excellent), blood pressure (below 120/80), fasting blood glucose (below 100 mg/dL), and cholesterol levels. Many people within the "ideal weight" range have poor metabolic health due to inactivity and poor diet, while others above ideal weight are metabolically healthy and fit.
The healthiest weight for you is one you can maintain with a sustainable eating pattern and exercise routine — not an arbitrary formula number that requires extreme restriction to reach.
Frequently Asked Questions
Is ideal weight different for men and women at the same height?
Yes. Women's ideal weight formulas are approximately 4.5 kg (10 lbs) lower than men's at the same height. This reflects differences in average bone density, muscle mass, and body composition between sexes. Women also naturally carry 5–8% more essential body fat than men. The Devine formula: men start at 50 kg for 5 feet; women start at 45.5 kg. Each additional inch adds 2.3 kg for both sexes.
What if I'm muscular — should I still aim for ideal weight?
No. Athletes and muscular individuals should disregard single ideal weight numbers. A 5'10" male bodybuilder might weigh 195 lbs at 8% body fat — well above the Devine ideal weight of 166 lbs — yet be in exceptional health. For muscular individuals, body fat percentage is a far more relevant metric than weight or BMI. Aim for healthy body fat (6–17% for men, 14–25% for women) rather than an arbitrary weight target.
How long does it take to reach a healthy weight?
A safe, sustainable rate of weight loss is 0.5–1% of bodyweight per week. For a 200 lb person, that's 1–2 lbs/week. Faster rates increase muscle loss and are harder to maintain. To lose 30 lbs safely takes approximately 15–30 weeks (4–7 months) at this pace. Focus on building sustainable habits rather than fastest results — people who lose weight quickly are significantly more likely to regain it.
