How to calculate your ideal weight
A few formulas turn your height into a rough target weight. Here is how they work, why they disagree, and why the result is a guide, not a goal.
Estimate a healthy target weight for your height using three well-known formulas.
"Ideal weight" sounds precise, but it is really a rough reference: a ballpark figure, worked out mostly from your height, that gives a rough idea of a healthy weight range. It is useful as a starting point and genuinely interesting to calculate, but it is not a personal health target, and the formulas that produce it disagree with each other by a fair amount. This guide shows the common ways to estimate it, works an example, and, just as importantly, explains what the number leaves out. It is general information, not medical or weight-loss advice.
Two ways to estimate your ideal weight
There are two common approaches, and they answer slightly different questions. The first is a healthy weight range from BMI, and the second is a single ideal body weight formula.
The BMI method is the more useful for most people, because it gives a range rather than one number. The World Health Organization treats a body mass index between 18.5 and 25 as the healthy range, and you can turn that back into a weight range for your height. BMI is weight in kilograms divided by height in metres squared, so for a height of 1.75 m, the healthy range is 18.5 × 1.75² up to 25 × 1.75², which is about 57 kg to 77 kg. Weights in that band fall in the WHO's "healthy" category on this one measure, which says nothing about your waist, fitness or blood work. The cut-offs are also adjusted for some groups, with lower thresholds recommended for people of South and East Asian descent. Our explainer on whether BMI is accurate covers the method and its big caveats.
The ideal body weight formulas
The other approach gives a single figure using a formula based on height and sex. Several exist, developed decades ago and still used, mainly in medicine for calculating drug doses rather than as health goals. They share the same shape: a base weight for a height of five feet, plus a fixed amount for each inch above that. The best known is the Devine formula (1974):
Men: 50 kg + 2.3 kg for each inch over 5 feet
Women: 45.5 kg + 2.3 kg for each inch over 5 feet
So for a man of 5 feet 10 inches (10 inches over five feet), the formula gives 50 + (2.3 × 10) = 73 kg, about 161 lb, one rough reference point rather than a target. Other formulas, such as Robinson, Miller and Hamwi, use slightly different base figures and per-inch amounts: for that same height they give roughly 71 kg (Robinson), 75 kg (Hamwi) and 70 kg (Miller), which is exactly why no single number is "the" ideal weight. A woman of 5 feet 4 inches gets 45.5 + (2.3 × 4) = 54.7 kg, about 121 lb, from the Devine formula.
Why the numbers disagree
If you run your height through several of these formulas, you will get several different answers, sometimes varying by 10% or more. That is not a mistake; it reflects that there is no single correct "ideal" weight. The formulas were built for different purposes and populations, and medical reviews (such as one in the NIH's PMC library) have found they diverge noticeably, by up to around 14% for some heights, especially for people who are very tall, very short, or far from average build. The spread between them is a useful reminder: treat any single number as the middle of a fuzzy range, not an exact target.
What these numbers leave out
This is the most important part. An ideal-weight figure is calculated almost entirely from height, so it ignores most of what actually determines a healthy weight for you:
Muscle and body composition. The formulas cannot tell muscle from fat. A fit, muscular person can weigh well above their "ideal" figure and be perfectly healthy, while someone at their ideal weight can carry too much body fat. For that, body composition matters more than the scale; see how to estimate body fat percentage, or try the body fat calculator.
Frame size, age and individual differences beyond the rough adjustment the formulas make.
Your health markers. Blood pressure, fitness, blood sugar and how you feel say far more about your health than a target weight does.
Because of this, an ideal-weight number is best used as a rough orientation, not a goal to chase. It can tell you if you are roughly in a typical range, but it cannot tell you what is healthy for your body.
A couple of quick rules (and their limits)
You will also see rougher rules of thumb. One subtracts 100 from your height in centimetres for men, or 105 for women, to give a weight in kilograms, so a man of 175 cm lands at about 75 kg. Another simply reads a weight off the healthy BMI band. These are even blunter than the named formulas and share all the same blind spots, so they are fine for a ballpark and useless as a precise target. Whatever method you use, the answer is a rough orientation, not a prescription.
These formulas are for adults
One important limit: every method here is built for adults. Children and teenagers grow in bursts, and a healthy weight for them is assessed with age-and-sex growth charts, not adult formulas or a single BMI cut-off. Pregnancy, older age and some medical conditions also change what a healthy weight looks like. If any of those apply, a height-based number is the wrong tool, and a doctor or dietitian is the right one.
A sensible way to use it
Treat the result as one data point among several. If a formula or the BMI range puts you well outside the typical band and that matches other signs, it may be worth a conversation with a doctor, who can look at the whole picture rather than a single number. If you are already a healthy weight, there is usually little to learn from the number itself. And if you are an athlete or carry a lot of muscle, expect these height-based numbers to understate your healthy weight, and lean on body-fat and fitness measures instead. One more thing: if thinking about your weight causes anxiety, or you have a history of disordered eating, it is best to skip these numbers entirely and speak to a doctor rather than chase a figure. For anything involving real health decisions, a qualified professional beats any formula.
The bottom line
You can estimate an ideal weight two ways: as a healthy range from BMI (18.5 to 25 times your height in metres squared), or as a single figure from a formula like Devine. Both start from your height, both disagree with each other, and both ignore muscle, frame and your actual health markers, so the result is a rough guide and never a personal target. To see the range and several formulas side by side, put your height into our ideal weight calculator, and check it against our BMI calculator. This is general information, not medical advice; for a weight that is right for you, talk to a doctor or dietitian.
Frequently asked questions
How do I calculate my ideal weight?
Two common ways. Turn the healthy BMI range into a weight range: multiply 18.5 and 25 by your height in metres squared. Or use a formula like Devine: for men, 50 kg plus 2.3 kg per inch over 5 feet; for women, 45.5 kg plus 2.3 kg per inch. Both are rough estimates based mainly on height.
What is the ideal weight for my height?
There is no single correct answer. A common healthy range comes from BMI: for a height of 1.75 m it is about 57 to 77 kg (a BMI of 18.5 to 25). Single-number formulas give a figure in that region but disagree with each other, so treat any result as the middle of a range, not an exact target.
Why do ideal weight calculators give different answers?
Because there is no single agreed formula. Devine, Robinson, Miller and Hamwi use different base weights and per-inch amounts, and can differ by 10% or more. They were designed for different purposes, mainly medical drug dosing, so the spread between them shows that ideal weight is a fuzzy range, not an exact number.
Is ideal weight the same as a healthy weight?
Not necessarily. Ideal-weight formulas are based almost entirely on height and ignore muscle, body fat, frame size and your health markers. A muscular person can be healthy well above their ideal figure. A healthy weight depends on body composition and overall health, not just a height-based number.
Should I use ideal weight as a goal?
It is better used as a rough orientation than a goal. The number cannot see your muscle, frame or health markers, so chasing it exactly can be misleading. If you are far outside the typical range, or making real health decisions, talk to a doctor or dietitian who can look at the whole picture.