Find your ideal body weight with our free online Ideal Weight Calculator, which uses four scientifically established formulas — Robinson (1983), Miller (1983), Devine (1974), and Hamwi (1964) — to provide a comprehensive range of ideal weight estimates for your height and gender. Rather than relying on a single formula, our tool calculates all four and presents the average, giving you the most balanced and realistic weight target. Ideal body weight (IBW) is a clinical concept used by healthcare professionals to estimate the weight at which a person is likely to be healthiest. It is widely used in medicine for drug dosing calculations (many medications are dosed based on IBW rather than actual weight), mechanical ventilation settings (tidal volume calculations), nutritional assessments, and setting realistic weight management goals. The four formulas our calculator uses are: • Robinson Formula (1983): For men: 52 kg + 1.9 kg per inch over 5 feet. For women: 49 kg + 1.7 kg per inch over 5 feet. This formula was developed through extensive clinical data analysis and is considered one of the most balanced approaches. • Miller Formula (1983): For men: 56.2 kg + 1.41 kg per inch over 5 feet. For women: 53.1 kg + 1.36 kg per inch over 5 feet. Miller's formula tends to produce slightly higher estimates and may be more appropriate for people with larger body frames. • Devine Formula (1974): For men: 50 kg + 2.3 kg per inch over 5 feet. For women: 45.5 kg + 2.3 kg per inch over 5 feet. Originally developed for drug dosing rather than weight management, the Devine formula is the most widely cited in medical literature and is used by many healthcare systems worldwide. • Hamwi Formula (1964): For men: 48 kg + 2.7 kg per inch over 5 feet. For women: 45.5 kg + 2.2 kg per inch over 5 feet. The Hamwi method was one of the first ideal body weight formulas and remains popular in clinical dietetics. All four formulas share a common structure — they start with a base weight for a height of 5 feet (152.4 cm) and add a specific amount per additional inch of height. The key difference between them is the increment per inch and the base weight, which leads to varying estimates. For most heights, the range between the lowest and highest formula is typically 3–7 kg, providing a realistic 'target zone' rather than a single number. Our calculator takes the average of all four formulas to provide the most representative estimate. This averaged approach smooths out the biases inherent in each individual formula and gives you a practical, evidence-based target weight to aim for. It is important to understand that ideal body weight is a general guideline, not an absolute rule. Individual factors such as body frame size (small, medium, or large), muscle mass, bone density, age, and ethnic background all influence what weight is healthiest for you. Athletes and people who weight-train regularly may have ideal weights significantly above these estimates due to increased muscle mass. Similarly, petite-framed individuals may find their healthiest weight is below the calculated ideal. The concept of ideal body weight has evolved significantly over time. Early tables from Metropolitan Life Insurance Company (1943, 1959, 1983) were based on mortality data and categorized ideal weights by frame size. The formulas used today are simplifications of these tables, designed for quick clinical calculation. Modern medicine increasingly recognizes that a range of weights can be 'ideal' and that overall fitness, body composition, and metabolic health markers are more important than hitting a specific number on the scale. For the most comprehensive assessment, combine your ideal weight result with your BMI (using our BMI Calculator), body fat percentage (using our Body Fat Calculator), and waist circumference. Together, these metrics provide a much clearer picture of your health status than any single measurement alone. All computations run entirely in your browser — no personal data is transmitted or stored. The tool is completely free, works on any device, and requires no registration.
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