Where "ideal body weight" comes from
The term entered medicine in the 1960s not as a fitness target but as a dosing tool. Many drugs, including the heart medication digoxin and certain antibiotics, must be calibrated to lean body mass rather than total body weight to avoid toxicity. Clinicians needed a quick way to estimate how much of a patient's weight was lean tissue, and simple height-based formulas filled that role. Over time, patients and the public started asking about these numbers in a different context, treating the formula output as a goal weight. That shift in meaning is important to understand before you apply any of the numbers below to yourself.
The National Institutes of Health (NIH) and the National Heart, Lung, and Blood Institute (NHLBI) both use BMI as the standard population-level measure of healthy weight, not the IBW formulas. The World Health Organization (WHO) likewise defines healthy weight as a BMI between 18.5 and 24.9. The CDC uses the same threshold for adults 20 and older.
The four classic ideal body weight formulas
All four formulas take height in inches and express the result in kilograms. The phrase "inches over 60" means the number of inches above 5 feet (60 inches).
Devine (1974)
The most widely cited formula in clinical pharmacology. It was published by B.J. Devine to estimate drug dosing for digoxin and remains the default in many hospital systems today.
- Men: 50 kg + 2.3 kg for each inch over 60
- Women: 45.5 kg + 2.3 kg for each inch over 60
Worked example: a 5 ft 10 in man (10 inches over 60) has a Devine IBW of 50 + (2.3 × 10) = 73 kg, which is about 161 lb. A 5 ft 4 in woman (4 inches over 60) has a Devine IBW of 45.5 + (2.3 × 4) = 54.7 kg, which is about 121 lb.
Hamwi (1964)
The oldest of the four, developed by G.J. Hamwi for use in managing patients with diabetes. It uses a slightly different base weight and a larger increment per inch.
- Men: 48 kg + 2.7 kg for each inch over 60
- Women: 45.5 kg + 2.2 kg for each inch over 60
Robinson (1983)
Published by J.D. Robinson and colleagues as a refinement of the Devine formula using a larger patient dataset. The increment per inch is smaller, which gives slightly lower results for taller individuals.
- Men: 52 kg + 1.9 kg for each inch over 60
- Women: 49 kg + 1.7 kg for each inch over 60
Miller (1983)
Also published in 1983, by D.R. Miller. It uses a higher base weight but the smallest per-inch increment of the four formulas, producing the highest results at shorter heights and the most moderate results at greater heights.
- Men: 56.2 kg + 1.41 kg for each inch over 60
- Women: 53.1 kg + 1.36 kg for each inch over 60
Formulas compared at one height
The table below shows what each of the four formulas produces for a 5 ft 8 in person (8 inches over 60), for both men and women.
| Formula | IBW men (5'8") | IBW women (5'8") |
|---|
| Devine (1974) | 68.4 kg / 151 lb | 63.9 kg / 141 lb |
| Hamwi (1964) | 69.6 kg / 153 lb | 63.1 kg / 139 lb |
| Robinson (1983) | 67.2 kg / 148 lb | 62.6 kg / 138 lb |
| Miller (1983) | 67.5 kg / 149 lb | 64.0 kg / 141 lb |
The spread across formulas is roughly 5 lb for men and 3 lb for women at this height. The formulas agree more closely at moderate heights and diverge more at very tall or very short statures. None of the four is universally accepted as more accurate than the others for health purposes.
Devine IBW versus the BMI healthy range, by height
The table below compares the Devine IBW estimate for men and women against the BMI healthy range (BMI 18.5 to 24.9) for each height. The healthy range is the figure backed by the WHO, CDC, and NHLBI for assessing weight-related health risk in adults. Notice that the Devine IBW for men and women often falls inside but toward the lower end of the healthy range, which illustrates that the formula points to one specific weight within a realistic band.
| Height | IBW men (Devine) | IBW women (Devine) | Healthy range (BMI 18.5 to 24.9) |
|---|
| 5 ft 0 in | 110 lb | 100 lb | 95 to 127 lb |
| 5 ft 2 in | 120 lb | 110 lb | 101 to 136 lb |
| 5 ft 4 in | 131 lb | 121 lb | 108 to 145 lb |
| 5 ft 6 in | 141 lb | 131 lb | 115 to 154 lb |
| 5 ft 8 in | 151 lb | 141 lb | 122 to 164 lb |
| 5 ft 10 in | 161 lb | 151 lb | 129 to 174 lb |
| 6 ft 0 in | 171 lb | 161 lb | 136 to 184 lb |
| 6 ft 2 in | 181 lb | 171 lb | 144 to 194 lb |
| 6 ft 4 in | 191 lb | 181 lb | 152 to 205 lb |
The healthy range column is the figure to actually use for day-to-day reference. It is a 30 to 50 lb window at most heights, which reflects the genuine diversity in healthy human bodies. A person at the top of that range who is muscular and active is not in worse health than one at the bottom. For a deeper look at the full chart across more heights, see our how much should I weigh article.
Why the formulas disagree with each other
Each formula was built from a different patient group, at a different hospital, in a different decade, for a different clinical purpose. Devine was working with digoxin patients; Hamwi with people managing diabetes; Robinson and Miller each tried to improve on Devine with their own samples. Because there was no shared reference population and no agreed-upon outcome to optimize for, the formulas naturally drift from each other. The differences are largest at extreme heights, where small differences in the per-inch increment compound over many inches above 5 feet.
A 2016 review in Nutrition in Clinical Practice examined all four formulas and found no clear winner for general use. The authors recommended using IBW formulas alongside BMI rather than as standalone targets, which aligns with current guidance from the NHLBI. For clinical drug dosing, pharmacists typically specify which formula to use on a per-drug or per-institution basis.
Ideal body weight versus healthy weight: what really matters
The IBW formulas share one significant limitation: they know only your height. They cannot see whether you are a trained athlete with dense muscle, an older adult with lower bone density, someone with a large natural frame, or a person who is slim but sedentary with high visceral fat. Two people of identical height can have very different healthy weights based on these factors, yet the IBW formula returns the same number for both.
Body composition tells a more complete story. The CDC defines healthy weight using BMI as a screening tool while acknowledging it does not measure body fat directly. The NIH and NHLBI recommend combining BMI with waist circumference to assess health risk, since excess abdominal fat is associated with higher risk of heart disease and type 2 diabetes even within the normal BMI range. A waist circumference above 35 inches for women or 40 inches for men indicates elevated risk, according to NHLBI guidance, regardless of where your weight sits on a chart.
Fitness level is another factor. Two people at the same weight and height can have very different cardiovascular fitness, strength, and metabolic health. WHO guidance emphasises that physical activity and dietary quality contribute to health outcomes independently of body weight. Reaching a lower number on the scale while remaining sedentary is not the same as reaching it through an active lifestyle.
How to use the ideal body weight result sensibly
Here is a practical approach to the numbers on this page:
- Find your height in the table above and note the BMI healthy range column. That is your primary reference band.
- Look at the Devine IBW figures for your height and sex. If your current weight is close to that number and within the healthy range, you are in good shape by these metrics.
- If your current weight is above the healthy range, any progress toward it reduces health risk. You do not need to reach the IBW single-point figure; reaching any point within the healthy range is the goal.
- If you are muscular or heavily built, your IBW may underestimate a healthy weight for you. Use waist circumference alongside the BMI range as a second check.
- Consult a healthcare provider before setting a specific target weight, especially if you have any underlying health conditions. The numbers here are population-level estimates, not individual prescriptions.
For a personalised healthy weight range based on your exact height and current weight, see our related article on what is a healthy BMI.