We use cookies to improve your experience. By continuing to use this site, you agree to our use of cookies.
Find your ideal body weight based on your height and sex using multiple scientific formulas. Compare results from Devine, Robinson, Miller, and Hamwi methods.
Ideal body weight (IBW) is an estimated weight that is considered optimal for a person's height and sex. Originally developed for pharmaceutical dosing calculations, IBW formulas have become widely used as general health references. Our calculator uses four well-established formulas — Devine, Robinson, Miller, and Hamwi — and provides their average for a balanced estimate.
The Devine formula (1974) is the most commonly used in clinical practice: Males = 50 + 2.3 kg per inch over 5 feet; Females = 45.5 + 2.3 kg per inch over 5 feet. The Robinson formula (1983) adjusts these values slightly. The Miller formula (1983) tends to give higher estimates, especially for shorter individuals. The Hamwi formula (1964) is one of the earliest and uses different increments for men and women. By averaging all four, you get a more balanced and reliable estimate.
Ideal weight formulas have significant limitations. They were developed primarily from Caucasian population data and may not be equally applicable to all ethnicities. They do not account for muscle mass, bone structure, body fat percentage, or age. Athletes and muscular individuals may have a healthy weight well above their calculated ideal weight. These formulas should be used as general guidelines rather than strict targets. The BMI-based healthy weight range provides a broader and often more practical reference.
The concept of 'ideal weight' has evolved significantly since the early 20th century when Metropolitan Life Insurance Company published its first height-weight tables in 1943, based on policyholder mortality data. These tables, revised in 1959 and 1983, showed the weight ranges associated with the lowest mortality rates for each height, categorized by 'frame size' (small, medium, large). While influential, they were criticized for their reliance on an insured, predominantly white, upper-middle-class population and the subjective nature of frame size determination. The medical community has since developed multiple formula-based approaches, each derived from different population studies and using different mathematical models. The Devine formula (1974), originally developed for calculating drug dosages rather than ideal body weight per se, became the most widely used clinical reference. The Robinson (1983) and Miller (1983) formulas were developed as improvements using updated population data. Modern research has shifted focus from single 'ideal' weight numbers to weight ranges associated with optimal health outcomes. Large-scale epidemiological studies, including the Global BMI Mortality Collaboration analysis of over 10 million participants across 239 studies, have demonstrated that the relationship between weight and mortality follows a J-shaped or U-shaped curve: both very low and very high weights are associated with increased mortality, with the lowest risk generally occurring in the BMI 20-25 range. However, this relationship is modulated by body composition, fitness level, metabolic health markers, and fat distribution pattern, leading many researchers to argue that fitness is a better predictor of health outcomes than weight alone.
Our calculator uses four established formulas, each with its own history and methodology, then averages them for a balanced estimate. The Devine Formula (1974): Originally published by Dr. B.J. Devine for pharmaceutical dosing. For males: IBW (kg) = 50 + 2.3 x (height in inches - 60). For females: IBW (kg) = 45.5 + 2.3 x (height in inches - 60). This formula sets a base weight for someone who is 5 feet (60 inches) tall and adds 2.3 kg for each additional inch. The Robinson Formula (1983): Developed by Dr. J.D. Robinson as a refinement. For males: IBW (kg) = 52 + 1.9 x (height in inches - 60). For females: IBW (kg) = 49 + 1.7 x (height in inches - 60). It uses a lower increment per inch, resulting in lower estimates for tall individuals and slightly higher estimates for shorter individuals compared to Devine. The Miller Formula (1983): Proposed by Dr. D.R. Miller. For males: IBW (kg) = 56.2 + 1.41 x (height in inches - 60). For females: IBW (kg) = 53.1 + 1.36 x (height in inches - 60). It has the highest base weight but the lowest per-inch increment, making it the most conservative for tall people. The Hamwi Formula (1964): The oldest formula, developed by Dr. G.J. Hamwi. For males: IBW (kg) = 48 + 2.7 x (height in inches - 60). For females: IBW (kg) = 45.5 + 2.2 x (height in inches - 60). In addition, our calculator shows the BMI-based healthy weight range, calculated by finding the weights corresponding to BMI 18.5 and 24.9 for your height. This range is often the most clinically useful reference because it accounts for the natural variation in healthy body weights.
Treat ideal weight calculations as a starting reference point, not a definitive target. Your personal ideal weight depends on many factors these formulas do not capture, including your body frame size, muscle mass, age, and overall health profile. A person with a larger bone structure or significant muscle mass may be perfectly healthy at a weight 10-20% above the formula-calculated ideal. Focus on health markers rather than a number on the scale: blood pressure below 120/80 mmHg, fasting blood glucose below 100 mg/dL, total cholesterol below 200 mg/dL, and a waist-to-hip ratio below 0.9 for men or 0.85 for women are all more meaningful indicators of health than matching an ideal weight formula. If you want to change your weight toward a healthier range, aim for gradual changes of 0.5-1 kg per week maximum. Rapid weight loss (more than 1 kg per week sustained) typically results in significant muscle loss alongside fat loss, which worsens body composition and metabolic health even if the scale number improves. Set performance-based goals alongside weight goals: being able to walk a certain distance, lift a certain weight, or complete specific physical activities provides motivation that is independent of scale numbers. Consider consulting with a sports medicine physician or registered dietitian who can assess your body composition, metabolic health, and physical fitness to determine a truly personalized healthy weight range. For older adults, maintaining a slightly higher weight (BMI 25-27) may actually be protective against frailty and falls, which is why the ideal weight concept must be applied with age-appropriate nuance.
While having a weight goal can be motivating, pursuing an unrealistic ideal weight carries both physical and psychological risks. The ideal weight formulas were developed from population averages and do not account for individual biological variation — setting your goal at the exact formula output ignores the reality that healthy weights span a range of approximately 10-15 kg for any given height. Chronically restricting calories to reach an artificially low target weight can trigger adaptive thermogenesis, where your body reduces metabolic rate by 10-15% below predicted levels, making further weight loss extremely difficult and weight regain almost inevitable. This metabolic adaptation was dramatically demonstrated in the 'Biggest Loser' study, which found that participants had significantly suppressed metabolic rates even 6 years after the competition. Weight cycling (repeatedly losing and regaining weight) is associated with increased cardiovascular risk, higher cortisol levels, loss of lean muscle mass with each cycle, and disordered eating patterns. The psychological impact of weight preoccupation can be equally damaging. Research published in the International Journal of Eating Disorders found that rigid dietary restraint and an all-or-nothing approach to weight goals are significant risk factors for developing eating disorders, which affect approximately 9% of the global population and have the highest mortality rate of any mental health condition. Body dysmorphia — a distorted perception of one's body size and shape — can develop when individuals become fixated on achieving a specific number. Instead of pursuing a single ideal weight, focus on weight stability within a healthy range, sustainable eating and exercise habits that you can maintain long-term, and health metrics beyond the scale that reflect your actual wellbeing.
The concept of ideal body weight has evolved significantly since the early 20th century. The first widely used reference was the Metropolitan Life Insurance height-weight tables, published in 1943 based on policyholder mortality data. These tables showed weight ranges associated with the lowest death rates for each height, categorized by frame size. While influential, they were criticized for relying on a non-representative population of insured, predominantly white, upper-middle-class Americans and for the subjective nature of frame size determination.
Four major formulas emerged to provide more objective, formula-based ideal weight estimates. The Devine formula (1974), originally developed by Dr. B.J. Devine for calculating drug dosages, sets a base weight of 50 kg for men and 45.5 kg for women at 5 feet tall, adding 2.3 kg per additional inch of height. The Robinson formula (1983) uses a higher base (52 kg for men, 49 kg for women) but a lower per-inch increment (1.9 kg for men, 1.7 kg for women), producing more conservative estimates for tall individuals. The Miller formula (1983) has the highest base weight (56.2 kg for men, 53.1 kg for women) with the lowest increment (1.41 kg for men, 1.36 kg for women). The Hamwi formula (1964), the oldest, uses 48 kg for men and 45.5 kg for women at 5 feet, with increments of 2.7 kg for men and 2.2 kg for women.
These formulas can produce significantly different results, especially for very tall or very short individuals. For a 6-foot tall male, the Devine formula gives 75.0 kg, Robinson gives 74.8 kg, Miller gives 73.1 kg, and Hamwi gives 80.4 kg, a spread of over 7 kg. This variation reflects the different populations and methodologies each researcher used. None of these formulas account for body composition, ethnicity, age, or individual variation in bone density and frame size, which is why they should be viewed as reference ranges rather than precise targets.
Modern health science increasingly favors BMI-based healthy weight ranges over single-point ideal weight targets. The range of weights corresponding to a BMI of 18.5 to 24.9 provides a broader and often more realistic representation of healthy weight for a given height. For a person 175 cm tall, the BMI-based healthy range spans roughly 56.7 to 76.3 kg, encompassing all four formula estimates and acknowledging the natural diversity of healthy body types. Research from the Global BMI Mortality Collaboration, analyzing over 10 million participants, found that the lowest all-cause mortality occurs in the BMI 20-25 range, supporting the use of a range rather than a single ideal number.
Our calculator applies four established formulas simultaneously. The Devine Formula: Males = 50 + 2.3 x (height in inches - 60), Females = 45.5 + 2.3 x (height in inches - 60). The Robinson Formula: Males = 52 + 1.9 x (height in inches - 60), Females = 49 + 1.7 x (height in inches - 60). The Miller Formula: Males = 56.2 + 1.41 x (height in inches - 60), Females = 53.1 + 1.36 x (height in inches - 60). The Hamwi Formula: Males = 48 + 2.7 x (height in inches - 60), Females = 45.5 + 2.2 x (height in inches - 60). All results are in kilograms.
The calculator also computes the BMI-based healthy weight range by solving the BMI formula in reverse: weight = BMI x height². For the lower bound, BMI 18.5 is used, and for the upper bound, BMI 24.9. The average ideal weight displayed is the arithmetic mean of all four formula results, providing a balanced estimate that moderates the individual biases of each formula. Height input in metric is converted to inches using the factor 1 inch = 2.54 cm before applying the formulas, and results can be displayed in both kilograms and pounds.