Devine
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Ideal Weight Calculator
There's no single 'ideal' weight — healthy is a range, not a number. This calculator shows three standard formulas plus your BMI-based healthy weight span.
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Healthy weight range
Robinson
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Miller
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BMI 18.5-24.9
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How these formulas work
Three formulas are used because no single formula is universally accepted as "correct" for ideal weight. The Devine formula (1974) was developed for hospital drug dosing, not for general health — it was built from data on height and weight from a 1974 study and was never intended to be a health target. The Robinson formula (1983) and Miller formula (1990) are refinements using similar methodology. All three were built from insurance company data on height and weight at different mortality rates — meaning they represent the weight at which people in those studies lived longest, not necessarily the weight at which any individual is healthiest. They all assume a medium frame; we apply a ±10% adjustment for small and large frames.
The BMI-based range (18.5–24.9) is the WHO's healthy weight range and is based on large-scale epidemiological studies linking BMI to health outcomes across populations. It is not perfect — it does not account for muscle mass, bone density, or ethnic differences in body composition. An Olympic athlete with 8% body fat may have a BMI of 27, which falls in the "overweight" category despite being clearly not overweight. Conversely, an elderly person with osteoporosis may have a "normal" BMI despite having excessive body fat.
Why 'ideal weight' is more complicated than a number
There is no single ideal weight that applies universally. A person's healthiest weight depends on muscle mass (which is heavier than fat), bone density (which varies by ethnicity and age), fat distribution (abdominal fat is more health-relevant than hip and thigh fat), age-related body composition changes, and individual health markers. The range produced by this calculator — combining the three formulas and the BMI range — is a better guide than any single number. Think of the range as approximately where most people at your height sit, not where you must be.
Body fat percentage is a more precise indicator of health than scale weight for many people. A man at 175 cm who weighs 80 kg with 15% body fat looks very different from one at 80 kg with 25% body fat, yet the scale reads the same. Body composition — the ratio of muscle to fat — matters more than the number on the scale. Resistance training can shift your body composition dramatically without changing your weight, which is why weight alone is a poor proxy for health.
Frequently asked questions
What is a healthy weight for my height?
A healthy weight for your height is the range within which population-level health outcomes are best — specifically a BMI of 18.5–24.9 for most adults. At 175 cm, this corresponds to approximately 57–76 kg. However, BMI does not measure muscle, so a muscular person at 80 kg may still be perfectly healthy despite being above the BMI range. Use the BMI-based range in this calculator as a guide and consider body fat percentage if you want a more precise health indicator.
Which formula should I use — Devine, Robinson, or Miller?
None of them is clearly better for general health purposes — they produce similar results that differ by only 2–4 kg. The Devine formula was designed for drug dosing, not health assessment, so Robinson or Miller are slightly more appropriate for health reference. The BMI-based range is probably the most evidence-based target for general population health. Treat all three formulas and the BMI range together as a reference band, not as precise targets.
What is the difference between ideal weight and healthy weight?
"Ideal weight" is the weight associated with the lowest mortality in insurance company data from the 1970s-1990s — essentially the weight at which people in those studies lived longest. "Healthy weight" is the range within which most health markers (blood pressure, cholesterol, blood sugar) are optimal. These are similar but not identical — people at the high end of the healthy BMI range often have similar health outcomes to those at the low end. The WHO defines healthy BMI as 18.5–24.9, which is slightly different from where the ideal weight formulas converge.
Does muscle mass affect the results?
Yes — significantly. Muscle is approximately 18% denser than fat, meaning the same body at 10% body fat weighs more than at 25% body fat. A 175 cm man with 80 kg at 15% body fat has approximately 12 kg of body fat and 68 kg of lean mass; gaining 5 kg of muscle through strength training while losing 5 kg of fat would still weigh 80 kg but look dramatically different and have a lower disease risk profile. This is why athletes often have BMI readings that classify them as overweight despite very low body fat. If you have significant muscle mass, use body fat percentage or waist circumference rather than weight-based formulas as your health metric.
Does bone density affect ideal weight?
Yes. Bone density varies by ethnicity, sex, age, and individual genetics. People of African descent tend to have higher bone density (and thus higher body weight for the same frame size) than people of European or Asian descent. Women generally have lower bone density than men. Osteoporosis (low bone density) is common in elderly women and can artificially lower their scale weight while increasing health risk. These formulas do not account for bone density differences, which is one reason they are less accurate for elderly populations.
Should I use this if I'm trying to lose or gain weight?
These formulas are most useful as a reference point, not as a target to force yourself toward. If your current weight is within the BMI range (18.5–24.9) and you feel healthy, focused, and energetic, the number on the scale is less important than your overall wellbeing. If you are significantly above this range and have associated health markers (elevated blood pressure, blood sugar, or cholesterol), gradual weight management may be medically beneficial. If you are below this range and are experiencing issues like missed periods (women), low energy, or weakened immune function, gaining weight may be appropriate. A healthcare provider can help you determine whether weight change is right for you.
How does age affect ideal weight?
With aging, muscle mass naturally declines (sarcopenia) and fat mass tends to increase even without weight change. This means the "ideal" weight for health may be slightly higher in older age — because maintaining sufficient muscle mass requires a higher total weight. Studies show that elderly individuals with a BMI of 25–27 often have better health outcomes than those at lower BMIs, partly because the extra weight reflects preserved muscle mass. The ideal weight formulas do not account for age-specific health targets, which is why the BMI range alone is more useful than the formula-based targets for older adults.
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For general wellness information only, not medical advice — see our disclaimer.