Ideal Weight Calculator

About the Ideal Weight Calculator

An ideal weight calculator estimates the weight range that is considered healthy and optimal for your height, sex, and frame size. The question how much should I weigh is one of the most searched health queries globally, reflecting a widespread desire for a concrete, evidence-based weight goal to aim for rather than the arbitrary numbers promoted by social media or fashion industry standards. Our free ideal weight calculator computes results using four of the most widely used and clinically referenced formulas: the Hamwi formula used by US military and healthcare providers, the Devine formula used in pharmaceutical dosing calculations, the Miller formula from academic research, and the BMI-based healthy weight range spanning BMI 18.5 to 24.9. It also shows the ideal weight according to body fat percentage targets for your sex — often a more meaningful metric for athletic or muscular individuals than scale weight alone. Understanding what constitutes a healthy weight range for your specific height helps you set realistic, evidence-based fitness goals instead of chasing arbitrary numbers. The important insight that all four formulas consistently deliver is that healthy weight is a range, not a single number. For a 5 foot 7 inch (170 cm) adult male, the various formulas suggest an ideal weight range of approximately 145 to 175 lbs (66 to 79 kg) — a 30-pound span that reflects genuine biological variation in bone density, muscle mass, frame size, and body composition. Someone near the upper end of this range with high muscle mass may be healthier than someone at the lower end who is sedentary with a high body fat percentage. This is why the ideal weight calculator presents results as a clinically informed range and encourages users to consider body composition alongside scale weight. The calculator covers adults in the USA, UK, Australia, Canada, and New Zealand with both metric and imperial inputs. Results should be interpreted as starting points for health conversations with your doctor or dietitian, not as rigid targets. Ideal body weight formulas were derived from population data and may not perfectly apply to every individual — especially those with unusual body compositions, significant muscle mass, or health conditions affecting weight and fluid balance.

How It Works

The four main ideal weight formulas use height above 5 feet, expressed as H = height in inches minus 60. The Hamwi method: Men = 106 lbs + 6 lbs per inch over 5 feet. Women = 100 lbs + 5 lbs per inch over 5 feet. Example: 5 foot 10 inch male: 106 + (10 x 6) = 166 lbs (75 kg). The Devine formula: Men = 50 kg + 2.3 kg per inch over 5 feet. Women = 45.5 kg + 2.3 kg per inch over 5 feet. For 5 foot 10: 50 + (10 x 2.3) = 73 kg (161 lbs). The Miller formula: Men = 56.2 kg + 1.41 kg per inch over 5 feet. Women = 53.1 kg + 1.36 kg per inch over 5 feet. For 5 foot 10: 56.2 + (10 x 1.41) = 70.3 kg (155 lbs). The BMI healthy range method: Minimum weight = 18.5 x height in metres squared; Maximum weight = 24.9 x height in metres squared. For 178 cm (1.78 m): 18.5 x 3.168 = 58.6 kg (129 lbs) to 24.9 x 3.168 = 78.9 kg (174 lbs). The formulas typically agree within 5 to 10 lbs but differ because they were derived from different population samples and time periods spanning the 1960s through the 1980s. The average of all four formulas generally provides the most robust estimate of population-based ideal body weight.

Tips & Best Practices

• ✓Ideal weight is a range, not a single number. Biological variation in bone density, muscle mass, and frame size means a healthy weight for your height can span 20 to 30 lbs depending on your individual body composition. Someone at the upper end of their ideal weight range with high muscle mass is not less healthy than someone at the lower end.
• ✓Muscle mass dramatically affects what an ideal weight looks like in practice: a 5 foot 10 inch male competitive bodybuilder might weigh 200 lbs at 8 percent body fat — well above any formula result — but is clearly healthy. Scale weight without body composition context is often misleading and should not be used as the sole measure of health.
• ✓The BMI healthy weight range of 18.5 to 24.9 is the most widely used clinical reference globally. For a 5 foot 5 inch woman, this corresponds to approximately 111 to 149 lbs — a 38-pound range that reflects genuine biological variation and means both ends of that spectrum can represent excellent health.
• ✓Frame size adjustment can be applied to formula results: large-framed individuals can healthily weigh approximately 10 percent above the formula result; small-framed individuals approximately 10 percent below. Measure wrist circumference to estimate frame size — women with wrist under 5.5 inches and men under 6.5 inches are small-framed.
• ✓Weight and health are not perfectly correlated: research consistently shows that cardiorespiratory fitness level predicts health outcomes better than scale weight alone. A fit person at the upper end of their ideal weight range is healthier than an unfit person at the lower end by most clinical outcome measures.
• ✓Children and teenagers have age- and sex-specific ideal weight ranges using BMI-for-age percentile charts from the CDC, WHO, or equivalent national health authorities. Adult formulas do not apply during active growth phases — use paediatric-specific tools for anyone under 18.
• ✓For body composition goals such as looking and feeling fit rather than hitting a specific scale number, targeting a body fat percentage of 12 to 17 percent for men or 20 to 25 percent for women (fitness category) is a more meaningful and actionable goal than a formula-derived weight.
• ✓Rapid weight loss targeting an ideal weight number causes muscle loss, hair loss, hormonal disruption, bone density reduction, and metabolic adaptation. Evidence-based weight management guidelines recommend aiming for 0.5 to 1 lb per week of loss maximum, with the lower end better for muscle preservation.

Who Uses This Calculator

People beginning a weight management programme use the ideal weight calculator to set a realistic, evidence-based target weight rather than an arbitrary goal influenced by social comparison or aesthetic ideals. Healthcare providers use ideal body weight (IBW) formulas — particularly the Devine formula — as a clinical reference for medication dosing calculations, anaesthesia dose estimation, and nutritional prescriptions in hospital settings where precision directly affects patient safety. Personal trainers and fitness coaches use ideal weight ranges to help clients set realistic goals that account for body composition rather than just scale numbers, preventing the common mistake of targeting an inappropriately low weight. Individuals struggling with body image use the calculator to understand that healthy weight is a range — and that their personal target does not need to be the absolute minimum of that range to be healthy and achieve their health goals. Parents track their children's growth against age-appropriate weight-for-height standards during paediatric appointments in the USA, UK, Australia, and New Zealand, though paediatric-specific growth charts should be used rather than adult formulas. Sports coaches use weight range information to help athletes in weight-class sports identify competitive weight classes that match their natural frame without requiring extreme and dangerous cutting protocols. Bariatric surgery programs use ideal body weight calculations to set post-operative weight loss goals and evaluate surgical outcomes.