Ideal body weight (IBW) for your height and sex by the Devine, Robinson, Miller and Hamwi formulas, with the healthy BMI weight range.
For your height the four formulas give 68.7–72 kg (Devine: 70.5 kg), and a healthy BMI corresponds to 56.7–76.6 kg.
Metric restatement of Hamwi's 106 lb at 5 ft plus 6 lb per inch above it. The original pound form gives 0.27 kg more at this height.
Ideal body weight (IBW) formulas start from a base weight at 5 ft (152.4 cm) and add a fixed amount for each inch above it. Devine (1974) uses 50 kg for men and 45.5 kg for women plus 2.3 kg per inch; Robinson, Miller and Hamwi use other bases and slopes. Beside them is the healthy weight range, the span that keeps BMI between the WHO cut-offs of 18.5 and 25.
Clinicians use IBW to dose some drugs and to set ventilator tidal volume, and many people use it as a reference weight. For a man 175 cm tall the four formulas give 68.7 to 72.0 kg, with Devine at 70.5 kg, while the healthy BMI range runs from 56.7 to 76.6 kg.
The equations come from old height-weight tables and ignore frame size, muscle and age. Below 5 ft they are extrapolated. Each gives a single number, whereas the BMI range shows how wide the healthy span is.
All four formulas take a base weight at 5 ft (60 in, 152.4 cm) and add a fixed amount for each inch above it. They differ in the base and the slope:
| Formula | Men | Women | Where it came from |
|---|---|---|---|
| Hamwi (1964) | 48 kg + 2.7 kg per inch | 45.5 kg + 2.2 kg per inch | A chapter on diet therapy in an American Diabetes Association book, stated in pounds |
| Devine (1974) | 50 kg + 2.3 kg per inch | 45.5 kg + 2.3 kg per inch | A clinical pharmacy case study on dosing gentamicin |
| Robinson (1983) | 52 kg + 1.9 kg per inch | 49 kg + 1.7 kg per inch | Regression on Metropolitan Life Insurance height and weight tables |
| Miller (1983) | 56.2 kg + 1.41 kg per inch | 53.1 kg + 1.36 kg per inch | A letter in the October 1983 issue of the journal that had published Robinson's paper in June |
Hamwi's original form is 106 lb plus 6 lb per inch for men and 100 lb plus 5 lb per inch for women, as restated in a 2025 Nutrients paper on nutrition after spinal cord injury. Devine's version appeared in 1974 in a case study by McCarron and Devine in Drug Intelligence and Clinical Pharmacy.
Pai and Paloucek (2000) traced all of them back to height and weight tables. Weight in those tables was found to track mortality, which is how the words "desirable" and "ideal" attached to it. Devine's equations matched an older rule of thumb drawn from the tables; once the handling of some drugs in the body was found to track IBW, Devine's version came into general use for dosing. Later regressions such as Robinson's produced similar lines.
Work out how many inches you are above 5 ft, multiply by the slope and add the base.
For a woman who is 5 ft 6 in, the excess is 6 in:
From centimetres, subtract 152.4 and divide by 2.54. A man who is 170 cm tall is (170 − 152.4) ÷ 2.54 = 6.929 in above 5 ft, so Devine gives 50 + 2.3 × 6.929 = 65.9 kg. The calculator carries the unrounded inches through and shows one decimal place.
To convert a result to pounds, divide the kilograms by 0.45359237. Devine's 59.3 kg is 130.7 lb.
Computed from the four formulas, in kilograms. The "all four" column shows the lowest and highest of the four results.
| Height | Men: Devine | Men: all four | Women: Devine | Women: all four |
|---|---|---|---|---|
| 5 ft 0 in (152 cm) | 50.0 | 48.0 to 56.2 | 45.5 | 45.5 to 53.1 |
| 5 ft 2 in (157 cm) | 54.6 | 53.4 to 59.0 | 50.1 | 49.9 to 55.8 |
| 5 ft 4 in (163 cm) | 59.2 | 58.8 to 61.8 | 54.7 | 54.3 to 58.5 |
| 5 ft 6 in (168 cm) | 63.8 | 63.4 to 64.7 | 59.3 | 58.7 to 61.3 |
| 5 ft 8 in (173 cm) | 68.4 | 67.2 to 69.6 | 63.9 | 62.6 to 64.0 |
| 5 ft 10 in (178 cm) | 73.0 | 70.3 to 75.0 | 68.5 | 66.0 to 68.5 |
| 6 ft 0 in (183 cm) | 77.6 | 73.1 to 80.4 | 73.1 | 69.4 to 73.1 |
| 6 ft 2 in (188 cm) | 82.2 | 75.9 to 85.8 | 77.7 | 72.1 to 77.7 |
| 6 ft 4 in (193 cm) | 86.8 | 78.8 to 91.2 | 82.3 | 74.9 to 82.3 |
At 5 ft 6 in and 5 ft 8 in the four results sit within 2.6 kg of each other for both sexes. At 6 ft 4 in the men's results are 12.4 kg apart, because Hamwi adds 2.7 kg per inch and Miller only 1.41 kg.
Dividing each formula's result by height in metres, squared, shows what BMI it implies. From 5 ft to 6 ft 4 in, every result lands inside the WHO normal range of 18.5 to 24.9, from 19.6 (Devine or Hamwi for a 5 ft woman) to 24.5 (Hamwi for a 6 ft 4 in man).
The formulas drift in different directions as height rises. Devine's weight for men implies a BMI of 21.5 at 5 ft and 23.3 at 6 ft 4 in, and Hamwi's rises from 20.7 to 24.5, so both favour a heavier build in tall men. Miller's falls from 24.2 to 21.1. Robinson's line for men stays between 22.1 and 22.6 over the whole span.
Shah and colleagues (2006) compared the formulas and published height-weight tables against a BMI of 22. They rated Robinson's formula the best fit for men, found that no formula came close to a BMI of 22 for women, and concluded that BMI ranges may be more useful in practice than IBW formulas.
Below 5 ft the formulas are extrapolated. The equations subtract per inch below 60 in, which none of them was built for. For a woman of 4 ft 8 in (142 cm), Devine gives 36.3 kg and Hamwi 36.7 kg, which correspond to a BMI of 17.9 and 18.1. Both fall below 18.5, the cut-off WHO uses for underweight in adults, so the "ideal" figure is one that WHO would class as too light. Miller gives 47.7 kg at the same height. The calculator warns whenever you enter a height under 5 ft.
Each formula gives one number per height and sex, with no allowance for build, age or muscle. Robinson's paper also derived separate equations for small, medium and large frames, but the widely used version, and the one here, is the all-frames line. A muscular person can sit well above their IBW with little fat; the body fat calculator measures that directly.
Published constants vary. The Robinson line used here and in most references, 52 kg + 1.9 kg per inch for men and 49 kg + 1.7 kg for women, is a rounded form. The original abstract gives 51.65 kg + 1.85 kg per inch and 48.67 kg + 1.65 kg per inch, which come out 0.8 kg lower for a 175 cm man and 0.5 kg lower for a 5 ft 4 in woman. Hamwi's pound form and its metric restatement drift apart as height rises: at 6 ft 4 in the pound form gives 0.4 kg more for a man and 0.9 kg more for a woman.
When a prescription or drug label gives a dose per kilogram of IBW, enter the IBW as the weight in the dosage by weight calculator. For a lean-mass estimate from your actual weight rather than your height alone, use the lean body mass calculator.
For a personal weight goal, compare the formulas with the healthy BMI range shown beside them. At 5 ft 6 in that range runs from 52.0 to 70.3 kg, and the four formulas place a woman of that height between 58.7 and 61.3 kg, in the middle third of it. The BMI calculator explains where that range comes from and what it misses.
Checked against: Python 3.8 decimal: 175 cm = 68.8976 in, 8.8976 in over 5 ft; 50 + 2.3 × 8.8976 = 70.4646 etc.; 18.5 × 1.75² and 25 × 1.75²
Checked against: Hand calculation, 4 in over 5 ft: 45.5 + 9.2, 49 + 6.8, 53.1 + 5.44, 45.5 + 8.8; BMI range by Python 3.8 decimal (1.6256 m)
Checked against: Published base weights at 60 in (Pai & Paloucek 2000)
Checked against: Hand calculation with −2 in over 5 ft: 45.5 − 4.6, 49 − 3.4, 53.1 − 2.72, 45.5 − 4.4
Men: 50 kg plus 2.3 kg for each inch over 5 feet. Women: 45.5 kg plus 2.3 kg per inch. A 5 ft 10 in man gets 50 + 2.3 × 10 = 73 kg, and a 5 ft 4 in woman gets 45.5 + 2.3 × 4 = 54.7 kg. B. J. Devine published it in 1974 in a paper on dosing the antibiotic gentamicin.
Mainly drug dosing and ventilator settings. Some drugs, such as aminoglycoside antibiotics, are dosed on IBW or an adjusted weight because they distribute poorly into fat. The ARDS Network's predicted body weight, 50 kg for men or 45.5 kg for women plus 0.91 kg per cm above 152.4 cm, is Devine's formula in centimetres, and lung-protective ventilation sets tidal volume at 6 ml per kg of it.
No formula is clearly better. A 2000 review by Pai and Paloucek traced all of them to the same height-weight tables and concluded that any one may be used to estimate IBW. At 175 cm the four agree within 3.3 kg for men (68.7 to 72.0 kg). They spread further apart at the extremes of height because the men's slopes differ, from 1.41 kg per inch (Miller) to 2.7 kg per inch (Hamwi).
No. IBW is one reference number per height, while a healthy weight is a range. WHO classes a BMI of 18.5 to 24.9 as normal, which at 175 cm spans 56.7 to 76.6 kg, about 20 kg. Any weight in that band counts as normal by the WHO population cut-offs, so an IBW figure is a reference point rather than a personal target.
Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 4 worked examples whose answers come from independent sources; for example, “Man, 175 cm” is checked against Python 3.8 decimal: 175 cm = 68.8976 in, 8.8976 in over 5 ft; 50 + 2.3 × 8.8976 = 70.4646 etc.; 18.5 × 1.75² and 25 × 1.75².
Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm 1974;8:650–655; Robinson JD, Lupkiewicz SM, Palenik L et al. Determination of ideal body weight for drug dosage calculations. Am J Hosp Pharm 1983;40:1016–1019; Miller DR, Carlson JD, Loyd BJ, Day BJ. Determining ideal body weight (and mass). Am J Hosp Pharm 1983;40:1622–1625; Hamwi GJ. Therapy: changing dietary concepts. In: Diabetes Mellitus: Diagnosis and Treatment. American Diabetes Association, 1964; Pai MP, Paloucek FP. The origin of the “ideal” body weight equations. Ann Pharmacother 2000;34:1066–1069; WHO. Obesity and overweight: overweight is a BMI of 25 or more; WHO Global Health Observatory: underweight among adults is a BMI below 18.5.
For information only, not medical advice. These formulas describe populations, not you; talk to a clinician before acting on a result.
4 worked examples with independently sourced answers ship with this calculator. They run in the test suite; you can run them here too.
Body mass index (BMI) from height and weight in metric or imperial units, with the WHO adult category and the healthy weight range for your height.
Body fat percentage by the US Navy tape method, Jackson-Pollock 3- or 7-site skinfolds, or from BMI, with fat and lean mass and the ACE category.
Lean body mass (LBM) from height, weight and sex by the Boer, James and Hume formulas, with the implied body fat percentage.
Dose by weight from a mg/kg rate and body weight, capped at the single and daily maximum, with the liquid volume in mL for a given strength.
Basal metabolic rate (BMR) by Mifflin-St Jeor, Harris-Benedict or Katch-McArdle, and daily calorie needs (TDEE) for five activity levels.
Waist-to-hip ratio and waist-to-height ratio from tape measurements, with the WHO risk cut-offs, the NICE bands and the WHO waist size category.
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