2026-06-26 · Calc-Tools Editor

Ideal Weight Chart: Standard Weight for Men and Women

Ask for the standard weight at a height of 170 cm and you may get several different answers. The plainest rule, height minus 100, returns 70.0 kg. The version printed on many clinic handouts, height minus 105, returns 65.0 kg. The Hamwi formula, widely used in American clinical settings, returns 66.7 kg. None of these is a miscalculation. They come from different formula families, fitted to different populations in different decades for different purposes. This guide lines the main methods up side by side, explains where the disagreement comes from, and shows which figure belongs to which situation. Every number below can be reproduced with the site's ideal weight calculator.

1. How Wide Is the Disagreement?

Start with the simplest comparison available. For an adult 170 cm tall, three rules that circulate widely give three different targets:

• Height minus 100 - the oldest rule, with no sex term: 70.0 kg for men and for women alike.
• Height minus 105 - the male version of the common revised rule: 65.0 kg.
• Height minus 107.5 - the female version of that same rule: 62.5 kg, which is 7.5 kg below the unisex figure.

Two subtractions, three answers, a spread of 7.5 kg. Bring in the inch-based clinical formulas and the results scatter anywhere between 60.7 kg and 66.7 kg. In other words, the phrase "standard weight" covers at least five or six distinct quantities, and the gap between them is wide enough to cross an entire weight category.

2. Where Each Formula Came From

These formulas were not written on the same day, and they were not written for the same job. Arranged by origin, three families appear: centimetre-linear rules, inch-based clinical rules, and range-based methods.

Two details deserve attention. First, five feet equals 152.4 cm, and every inch-based formula measures from that anchor, adding its own coefficient for each 2.54 cm above it. Second, only the last row was designed for health screening at all. The Hamwi formula served dietary prescriptions; the Devine formula served drug dosing. When a hospital or pharmacy says "ideal body weight", it normally means the latter. Using a dosing formula to decide whether you are overweight is a transfer of purpose, and it explains a great deal of the confusion.

3. Three Reasons the Formulas Disagree

The disagreement comes from three independent sources.

Different reference populations. These equations were fitted to physique data from specific decades, countries and occupations - soldiers, insurance policyholders, outpatients. Measuring a person today against the average build of a group recorded sixty years ago carries a systematic offset.

Different fitting targets. In clinical writing, "ideal body weight" often means a working reference value for a calculation, not the healthiest possible weight. The same phrase means an aspirational target in consumer health writing and a calculation parameter in dosing. The two are not interchangeable.

Different sensitivity to height. Work out how much each formula moves per centimetre of height and the picture sharpens: the Broca family adds 1.00 kg per cm, the male Hamwi 1.06 kg, Devine 0.91 kg, the male Robinson 0.75 kg, and the male Miller only 0.56 kg. The fastest is nearly double the slowest.

That difference in slope turns into a large absolute gap at the ends of the height range. Compare the original Broca rule with the male Miller formula: at 155 cm they give 55.0 kg and 57.6 kg, so Miller sits higher; at 180 cm they give 80.0 kg and 71.5 kg, and Broca is ahead by 8.5 kg. No formula is permanently high or permanently low - which one overshoots depends on where you stand on the height axis.

One coincidence is worth pausing over. The female "height minus 107.5" rule and the female Miller formula both return 62.5 kg at 170 cm, which looks like mutual confirmation. Step down to 155 cm and the female Miller formula gives 54.5 kg against 47.5 kg - a 7.0 kg gap. Step up to 180 cm and the order reverses: 72.5 kg against 67.9 kg. Two methods agreeing at a single height proves nothing about whether they agree in general, which is why "which formula is most accurate" has no answer unless a height range is specified.

4. Six Methods Compared at 170 cm

Putting the point-estimate formulas and the range method in one table shows the full picture. The back-calculated BMI column divides the formula's result by height in metres squared, which reveals the weight category that result would fall into.

The six point estimates for men sit between 65.0 kg and 70.0 kg, a spread of 5.0 kg. For women they run from 60.7 kg to 70.0 kg, a spread of 9.3 kg - the extra distance comes almost entirely from the unisex Broca rule, which reads high for women.

The most instructive cell in the table is in the last column. The Broca rule hands men a target of 70.0 kg, which back-calculates to a BMI of 24.2 - already inside the overweight band under the Chinese adult standard, where the cut-off is 24.0 - while the BMI range method in the same table puts the upper limit of normal at 69.1 kg. For one height, one method treats 70 kg as the goal and another treats it as over the line.

One easily overlooked detail: how a formula is transcribed also changes the answer. The American formulas above are evaluated in their original inch form. Chinese-language sources often rewrite them as centimetre rules, for example turning Devine into "50 + 0.9 times (height minus 152)". That rewrite moves the anchor from 152.4 cm to 152 cm and rounds 2.3 kg per inch to 0.9 kg per cm, which shifts the male 170 cm result from 65.9 kg to 66.2 kg - about 0.3 kg. Small, but it is a reminder that "the same formula" is not always the same number once it has been copied a few times.

5. Three Worked Examples

Example 1: a man of 170 cm, all six point estimates. At 170 cm the height is 66.93 inches, or 6.93 inches above five feet. Height minus 100 gives 70.0; height minus 105 gives 65.0; Hamwi gives 48.0 + 2.7 x 6.93, about 66.7; Devine gives 50.0 + 2.3 x 6.93, about 65.9; Robinson gives 52 + 1.9 x 6.93, about 65.2; Miller gives 56.2 + 1.41 x 6.93, about 66.0. The lowest and highest differ by 5.0 kg, an order of magnitude more than the ordinary day-to-day fluctuation of body weight.

Example 2: a woman of 160 cm, and the cost of dropping the sex term. At 160 cm the height is 62.99 inches, or 2.99 inches above five feet. The unisex Broca rule returns 60.0 kg, a BMI of about 23.4. The female height-minus-107.5 rule returns 52.5 kg, a BMI of about 20.5. The female Hamwi formula gives 45.5 + 2.2 x 2.99, about 52.1 kg, a BMI of about 20.3. The largest gap at this height is 7.9 kg. The cause is straightforward: the older rule carries no sex term, and men and women of the same height do not share the same lean mass or fat distribution. Applying a unisex rule to women reads systematically high.

Example 3: a man of 175 cm, where an old rule meets a new standard. The Broca rule gives 175 minus 100, or 75.0 kg. Dividing by 1.75 squared back-calculates a BMI of about 24.5, and three contradictory verdicts follow. Under the Chinese adult standard, where overweight starts at 24.0, 75.0 kg counts as overweight. Under the WHO international standard, where overweight starts at 25.0, the same 75.0 kg is still normal. The BMI range method under the Chinese standard puts the upper limit of normal at 23.9 x 1.75 squared, about 73.2 kg, so 75.0 kg falls outside the range entirely. One weight, three labels: target, overweight, and normal.

6. Which Method Fits Which Purpose

No method is better in the abstract; each is better for something. The table below matches methods to situations.

If you only want to know roughly where you sit, take a reading from the BMI calculator and convert it into a weight range with the ideal weight calculator - that path is simpler than memorising formulas. For the difference between the standards themselves, see the comparison of BMI normal ranges.

7. Five Common Misconceptions

Misconception 1: there is one correct standard weight. A 5 to 9 kg spread at the same height is normal. There is no single most accurate formula, only one that suits a given purpose.

Misconception 2: comparing across methods. Taking a figure from one formula and judging it against another formula's acceptable band stacks two different baselines on top of each other, and the few kilograms of difference hide that.

Misconception 3: treating a dosing formula as a health standard. Formulas such as Devine exist to calculate drug doses. The number they produce serves drug distribution, not health screening.

Misconception 4: ignoring the sex term and the age factor. Several older rules have no sex term, which reads high for women. Age matters too: height tends to shrink with age and muscle mass changes, so a target set at 30 means something different at 60 and needs to be revisited.

Misconception 5: equating a weight number with health. Weight reflects total mass, not fat distribution or the muscle-to-fat ratio. Waist measurement and body fat percentage answer different questions, and the thresholds that apply to you should come from officially published guidance and your own doctor.

8. Frequently Asked Questions

Why can different formulas differ by several kilograms?

Three causes overlap: different reference populations (different decades, countries and occupations), different fitting targets (some aim at the healthiest weight, others only at a working reference value), and different sensitivity to height (each extra centimetre of height adds anywhere from 0.56 kg to 1.06 kg depending on the formula). The gap is a design difference, not an arithmetic error.

Who is the Devine formula for, and can it tell me whether I am overweight?

It was published in 1974 for drug dose calculation and remains the reference used in hospitals and pharmacies when dosing by body weight. Using it to judge whether your weight is healthy is a transfer of purpose: it can serve as a reference point, but it is not a screening tool. For anything involving medication, follow the method your doctor or pharmacist uses.

Is a standard weight from an old formula still normal today?

Not necessarily. For a man of 170 cm, height minus 100 returns 70.0 kg, a BMI of about 24.2, which falls inside the overweight band under the Chinese adult standard, while the BMI range method puts the upper limit of normal at about 69.1 kg for the same height. An old formula's target can sit on the wrong side of a current cut-off, which is exactly why it is worth re-checking against the standard in force.

Why is the range derived from BMI so much wider than a formula result?

Because the two produce different kinds of quantity. A formula gives a point estimate, a single target number. A BMI range gives an interval, the span considered acceptable. At 170 cm that span is roughly 15.6 kg wide, far wider than the 5.0 kg that separates the six point estimates. The interval means "anything inside is normal", not "closer to the midpoint is better".

Which number should I actually aim for?

Work with an interval rather than a single point. Confirm which standard you are referencing, set your goal somewhere sensible inside the range, and read it alongside waist measurement, body fat percentage and your long-term trend. If your weight sits well outside the range, or changes sharply, or if you are pregnant, still growing, or managing a chronic condition, talk to a qualified doctor rather than relying on any formula.

9. Practical Advice

• Record the method before the number: note which formula or standard you used each time, so that months later you are not comparing figures built on different baselines.
• Use a range, not a point: a target band you are allowed to move inside is easier to hold for years than one exact figure.
• Keep weighing conditions constant: same scale, first thing in the morning, after using the bathroom. Judge the trend over three months or more rather than reacting to a single reading.
• Track at least one distribution measure: waist measurement or body fat percentage alongside weight. Weight alone can miss the case where the number holds steady while waist measurement climbs.
• Leave individual judgement to professionals: formulas describe where a population tends to sit, not what is right for you. If your weight shifts sharply, or you are pregnant, growing, or living with a chronic condition, consult a qualified doctor instead of substituting a formula for medical assessment.

To turn a range into a daily energy plan, pair these figures with the calorie calculator; to reproduce any number in this article, enter your height in the ideal weight calculator or the BMI calculator.