Ideal body weight (IBW) is an estimate of a healthy weight based on height and sex, not a goal for everyone. The Devine formula gives 50 kg + 2.3 kg per inch over 5 feet for men and 45.5 kg + 2.3 kg per inch for women. For a woman who is 5′5″ tall, that is about 126 lb (57 kg). Healthy-BMI weight is a wider and more useful range.
Key takeaways
- IBW formulas were built for drug dosing and clinical use, not as personal body-weight targets.
- The four common formulas (Devine, Robinson, Miller, Hamwi) differ by up to about 8 lb at 5′5″, so treat the result as a range.
- Adjusted body weight equals IBW plus 40% of the excess, and clinicians use it when actual weight is above 120% of IBW.
- A weight range for your height based on BMI 18.5–24.9 is a more realistic target than a single number.
How does this ideal weight calculator work?
Enter your sex and height, and optionally your current weight. The calculator shows the Robinson result as the headline figure, all four formulas (Devine, Robinson, Miller and Hamwi) in a table, their average, and the weight range that gives a BMI of 18.5–24.9 at your height.
If you add your current weight, it also shows how it compares with IBW as a percentage, and your adjusted body weight when you are above 120% of IBW. For heights under 5 feet, it notes that the formulas aren’t designed for you.
What is the ideal body weight formula?
All four formulas start from a base weight at 5 feet and add a fixed amount for each inch above it. They differ only in those constants (Devine, 1974; Robinson et al., 1983).
Devine: men 50 + 2.3 × inches over 5 ft; women 45.5 + 2.3 × inches over 5 ft Robinson: men 52 + 1.9 × inches over 5 ft; women 49 + 1.7 × inches over 5 ft Miller: men 56.2 + 1.41 × inches over 5 ft; women 53.1 + 1.36 × inches over 5 ft Hamwi: men 48 + 2.7 × inches over 5 ft; women 45.5 + 2.2 × inches over 5 ft
Devine’s original 1974 formula was written for drug dosing (Devine, 1974). Robinson and Miller were later proposed as revisions (Robinson et al., 1983; Miller et al., 1983), and Hamwi is an older rule of thumb (Hamwi, 1964).
Worked example
A woman who is 5′5″ (165 cm) is 5 inches over 5 feet.
| Formula | Calculation | Ideal weight |
|---|---|---|
| Devine | 45.5 + 2.3 × 5 | 57.0 kg (126 lb) |
| Robinson | 49 + 1.7 × 5 | 57.5 kg (127 lb) |
| Miller | 53.1 + 1.36 × 5 | 59.9 kg (132 lb) |
| Hamwi | 45.5 + 2.2 × 5 | 56.5 kg (125 lb) |
| Average | 127 lb (57.7 kg) |
Her healthy-BMI weight range at this height is 111–150 lb (50–68 kg). The formulas land in the lower-middle of it.
Ideal body weight chart by height
These values use the Robinson and Devine formulas. They are not shown below 5′0″ because the formulas are not defined there (4′10″: n/a).
| Height | Women: Robinson | Women: Devine | Men: Robinson | Men: Devine |
|---|---|---|---|---|
| 4′10″ | n/a | n/a | n/a | n/a |
| 5′0″ | 108 lb (49 kg) | 100 lb (46 kg) | 115 lb (52 kg) | 110 lb (50 kg) |
| 5′2″ | 116 lb (52 kg) | 110 lb (50 kg) | 123 lb (56 kg) | 120 lb (55 kg) |
| 5′4″ | 123 lb (56 kg) | 121 lb (55 kg) | 131 lb (60 kg) | 131 lb (59 kg) |
| 5′6″ | 131 lb (59 kg) | 131 lb (59 kg) | 140 lb (63 kg) | 141 lb (64 kg) |
| 5′8″ | 138 lb (63 kg) | 141 lb (64 kg) | 148 lb (67 kg) | 151 lb (68 kg) |
| 5′10″ | 146 lb (66 kg) | 151 lb (69 kg) | 157 lb (71 kg) | 161 lb (73 kg) |
| 6′0″ | 153 lb (69 kg) | 161 lb (73 kg) | 165 lb (75 kg) | 171 lb (78 kg) |
| 6′2″ | 160 lb (73 kg) | 171 lb (78 kg) | 173 lb (79 kg) | 181 lb (82 kg) |
| 6′4″ | 168 lb (76 kg) | 181 lb (82 kg) | 182 lb (82 kg) | 191 lb (87 kg) |
What is adjusted body weight?
When someone weighs much more than IBW, drug doses and some energy estimates are based on an adjusted weight, because dosing on full weight overestimates what the body needs.
adjusted body weight = IBW + 0.4 × (actual weight − IBW)
The 0.4 factor is the convention used in the calculator, applied when actual weight exceeds 120% of IBW. For a 5′5″ woman weighing 220 lb, Robinson IBW is 126.8 lb, so she is at 174% of IBW and her adjusted body weight is 74.4 kg (164 lb).
What are IBW formulas actually used for?
They come from clinical pharmacy, where some drugs are dosed by ideal or adjusted weight rather than total weight (Devine, 1974; Robinson et al., 1983). Doses are set by a clinician; never use this page to dose any medication.
Are ideal weight formulas accurate for me?
Not as a personal target. They use height and sex only, so they ignore muscle mass, bone structure, age and health. A muscular 5′10″ man can sit well above 160 lb with a healthy body composition, while someone with low muscle mass can sit at IBW and still carry high body fat.
A BMI-based range is a better guide, and the BMI calculator explains its own limits (WHO; CDC). For body composition, use the body fat calculator and the lean body mass calculator. If you are working toward a goal weight, the calorie deficit calculator estimates a timeline.
For a medical view of what weight is healthy for you, talk to your doctor or a registered dietitian.
Frequently asked questions
What is the ideal weight for my height?
For a woman 5′5″ tall, ideal body weight formulas give roughly 125–132 lb (57–60 kg), and a healthy-BMI range is about 111–150 lb. For a man 5′10″, formulas give about 155–165 lb. The chart on this page lists every height from 5′0″ to 6′4″.
What is the ideal weight for a female?
Female IBW formulas start at 45.5 kg (100 lb) at 5 feet and add about 2.3 kg (Devine) or 1.7 kg (Robinson) per extra inch. For a 5′4″ woman that is 121–123 lb. Frame size, muscle and age matter, so use these numbers as a reference point only.
What is adjusted body weight?
Adjusted body weight is IBW + 0.4 × (actual weight − IBW). Clinicians use it for drug dosing when actual weight is much higher than ideal. For example, a 5′5″ woman weighing 220 lb has an adjusted body weight of about 164 lb using Robinson IBW.
Which ideal body weight formula is best?
None is best for everyone. Devine is the most widely used in clinical dosing; Robinson and Miller were proposed as revisions; Hamwi is a quick rule of thumb. They agree within roughly 10 lb for most heights, so the average of all four is a sensible single figure.
Is ideal body weight the same as a healthy weight?
No. IBW is a single number from a height-based formula, whereas a healthy weight is a range that depends on body composition, age, health and goals. A muscular person can weigh well above IBW and be healthy. Talk to your doctor about what is right for you.
Do these formulas work for people under 5 feet?
They were not designed for it. Devine, Robinson, Miller and Hamwi start from a 5-foot baseline and add a value per inch above it, so results below 5′0″ are not reliable. Use the BMI-based healthy weight range instead.
References
- Devine BJ (1974). Gentamicin therapy. Drug Intelligence & Clinical Pharmacy 8:650–655.
- Robinson JD, Lupkiewicz SM, Palenik L, Lopez LM, Ariet M (1983). Determination of ideal body weight for drug dosage calculations. American Journal of Hospital Pharmacy 40(6):1016–1019.
- Hopefl AW, Miller DR, Carlson JD, Lloyd BJ, Day BJ, Tate M, Robinson JD, Lopez LM, Ramachandra CL (1983). Determining ideal body weight (and mass). American Journal of Hospital Pharmacy 40(10):1622–1627.
- Hamwi GJ (1964). Therapy: changing dietary concepts. In: Danowski TS, ed. Diabetes Mellitus: Diagnosis and Treatment. American Diabetes Association.
- World Health Organization (2024). Obesity and overweight — fact sheet. World Health Organization.
- Centers for Disease Control and Prevention (2024). Adult BMI Calculator and categories. U.S. Centers for Disease Control and Prevention.