What is ideal body weight?

Ideal body weight (IBW) is a target weight range deemed healthy for a person of a given height and sex. The concept has been around for over 100 years and is used by doctors for drug dosing (some medications dose based on IBW, not actual weight), insurance underwriting, military and athletic recruitment, and personal fitness goals. Multiple formulas exist – Devine (1974), Hamwi (1964), Robinson (1983), Miller (1983) – each developed for slightly different populations. They all give similar but not identical results. This calculator shows all four formulas plus their average, giving you a range rather than a single number. Real ideal weight depends on body composition (muscle vs fat), bone structure, age, and personal health goals – the formulas are screening tools, not strict targets.

How to use this tool

1. Select unit system — Metric (cm) or Imperial (inches).
2. Choose sex — Male or female. Formulas differ by sex because of typical body composition differences.
3. Enter height — In cm (metric) or inches (imperial). 5 ft 10 in = 70 inches = 177.8 cm.
4. Read results — Average ideal weight (top), range across formulas (sub-text), and individual formula results.

Ideal weight formulas (all in pounds, then converted)

All formulas use height in inches. For metric input, height is converted internally (1 inch = 2.54 cm).

Men:

• Devine (1974): IBW = 50 + 2.3 × (inches over 5 ft)
• Hamwi (1964): IBW = 48 + 2.7 × (inches over 5 ft)
• Robinson (1983): IBW = 52 + 1.9 × (inches over 5 ft)
• Miller (1983): IBW = 56.2 + 1.41 × (inches over 5 ft)

Women:

• Devine: IBW = 45.5 + 2.3 × (inches over 5 ft)
• Hamwi: IBW = 45.5 + 2.2 × (inches over 5 ft)
• Robinson: IBW = 49 + 1.7 × (inches over 5 ft)
• Miller: IBW = 53.1 + 1.36 × (inches over 5 ft)

Each starts with base weight at 5 feet (60 inches) and adds a fixed amount per inch above. Results in kg shown here.

Examples

• 5’10” male (177.8 cm): Devine 73, Hamwi 75, Robinson 71, Miller 70. Average ~72 kg.
• 5’4” female (162.6 cm): Devine 54.6, Hamwi 54.3, Robinson 55.8, Miller 58.6. Average ~56 kg.
• 6’2” male (188 cm): Devine 83.4, Hamwi 87.6, Robinson 80.5, Miller 76.5. Average ~82 kg.
• 5’7” female (170 cm): Devine 61.7, Hamwi 61, Robinson 60.9, Miller 62.6. Average ~62 kg.
• 5’2” male (157.5 cm): Devine 54.6, Hamwi 53.4, Robinson 55.8, Miller 59. Average ~55 kg.

Tips & best practices

• IBW is a guideline, not a strict target. Healthy weight depends on body composition – a muscular athlete may exceed IBW but be very fit
• Use BMI 18.5-24.9 range as an alternative healthy weight target – often gives slightly different numbers than IBW formulas
• Frame size affects ideal weight: small frame +/- 10% from IBW, large frame +10% from IBW
• Aging tends to add some weight – 60+ year olds may carry 5-10 lbs above young-adult IBW without health risk
• If your current weight is far from IBW, target gradual change (0.5-1 kg/week) – crash dieting fails long-term
• Track body composition (body fat %, lean mass) more than weight – building muscle while losing fat may not change scale weight

Limitations & notes

All IBW formulas were developed decades ago, primarily on Western populations, and may not apply equally to Asian, African, or mixed-heritage individuals. They don’t account for: muscle mass (athletes weigh more, are healthy), frame size (broad vs slim builds), age (some weight gain normal with age), ethnicity (Asians may have higher metabolic risk at lower BMI). Always consult a healthcare provider for personalized health weight targets – especially if you have medical conditions or athletic goals.

Frequently Asked Questions

Which ideal weight formula is most accurate?

None is ‘most accurate’ – they were developed for different purposes. Devine (1974) is most commonly used in clinical medicine for drug dosing. Robinson and Miller give slightly different ranges for shorter people. Use the average of all four for general guidance, or BMI 18.5-24.9 as an alternative.

Is my ideal weight my goal weight?

Not necessarily. IBW is an average-population health target. Your personal goal weight depends on body composition goals (more muscle = higher weight at same body fat %), aesthetic preferences, sports performance needs, and life stage. Many fit athletes weigh ABOVE ‘ideal’ due to muscle mass.

Should I lose weight to reach my ideal weight?

If you’re significantly above IBW AND have unhealthy body fat % (over 25% for men, 32% for women), then weight loss benefits health. If you’re above IBW but lean and muscular, you don’t need to lose weight – you’re healthy. Body composition matters more than scale weight.

How is ideal weight different from healthy weight range?

Healthy weight range (typically BMI 18.5-24.9) gives a band – say 56-75 kg for 170 cm tall person. Ideal weight gives a single target – say 66 kg. Most people aim for a range within the healthy range, picked based on personal goals and body type.

Does ideal weight change with age?

The formulas don’t account for age – they give the same number for a 25-year-old and 65-year-old of the same height/sex. In practice, some additional weight (5-10 lbs) is normal and healthy with age, especially if it’s muscle. Sarcopenia (muscle loss after 60) means scale weight may stay same while body fat increases.

Why are formulas different for men and women?

Women typically have different body composition (more essential fat, narrower shoulders, wider hips) than men of the same height. The base weight at 5 feet and the per-inch gain are both lower for women. This reflects population averages – individual variation is large.

Should I aim for the lowest IBW formula result?

No – the lowest formula isn’t ‘better.’ Each formula was developed differently. The average across all four gives a more balanced target. And IBW isn’t a strict cap – being slightly above with good body composition is healthier than being below with low muscle mass.

Related tools

BMI Calculator · Body Fat Calculator · Lean Body Mass