Ideal Weight Calculator
Calculate your ideal body weight using multiple clinically validated formulas.
What is ideal body weight?
Ideal body weight (IBW) is a clinical estimate of how much a person should weigh based on their height and sex. Originally developed in the 1970s for calculating medication dosages in hospitals, IBW formulas are now also used as a rough benchmark for fitness and nutrition goals. It is important to understand that these numbers are population averages — they do not account for muscle mass, bone density, age, or ethnicity, and should never be treated as a target weight for every individual.
The three formulas explained
Three formulas are in widespread use today. Each was derived from a different dataset and produces slightly different results. All three use height in inches and produce an estimate in kilograms.
Devine formula (1974)
Proposed by Dr. B.J. Devine, this is the most frequently cited formula in medical literature and is built into most drug-dosing software. It was originally derived from actuarial data and has remained the clinical standard for more than five decades.
Men: IBW = 50 + 2.3 × (height_in_inches − 60)
Women: IBW = 45.5 + 2.3 × (height_in_inches − 60)Robinson formula (1983)
J.D. Robinson revised the Devine formula using a different reference population. It tends to produce slightly higher estimates for men and slightly lower ones for women compared to Devine, and is considered more accurate for taller individuals.
Men: IBW = 52 + 1.9 × (height_in_inches − 60)
Women: IBW = 49 + 1.7 × (height_in_inches − 60)Miller formula (1983)
D.R. Miller's formula generally produces the lowest estimates of the three and is occasionally preferred for patients with a smaller body frame. Like the others, it assumes a baseline height of 5 feet (60 inches).
Men: IBW = 56.2 + 1.41 × (height_in_inches − 60)
Women: IBW = 53.1 + 1.36 × (height_in_inches − 60)Comparison table at common heights
| Height | Devine (M/F) | Robinson (M/F) | Miller (M/F) | BMI range (M/F) |
|---|---|---|---|---|
| 160 cm (5'3") | 55.3 / 50.8 kg | 56.0 / 53.2 kg | 59.0 / 56.2 kg | 47.4–63.7 kg |
| 165 cm (5'5") | 60.9 / 56.4 kg | 61.6 / 57.8 kg | 63.3 / 60.0 kg | 50.4–67.8 kg |
| 170 cm (5'7") | 66.5 / 62.0 kg | 67.2 / 62.4 kg | 67.6 / 63.9 kg | 53.5–72.0 kg |
| 175 cm (5'9") | 72.1 / 67.6 kg | 72.8 / 67.0 kg | 71.9 / 67.7 kg | 56.7–76.3 kg |
| 180 cm (5'11") | 77.7 / 73.1 kg | 78.5 / 71.6 kg | 76.2 / 71.6 kg | 59.9–80.6 kg |
| 185 cm (6'1") | 83.3 / 78.7 kg | 84.1 / 76.2 kg | 80.5 / 75.5 kg | 63.2–85.1 kg |
IBW versus the healthy BMI range
The healthy BMI range (18.5–24.9 kg/m²) typically yields a wider weight span than any single IBW formula. For most people, the BMI range is a more useful target because it acknowledges individual variation. For example, a 175 cm man with significant muscle mass might weigh 85 kg and have very low body fat — well above the Devine estimate of 72 kg, yet perfectly healthy.
Limitations of ideal body weight formulas
All three formulas share the same fundamental limitations. They were derived from mid-20th-century Western populations and do not adjust for:
- Muscle mass: Athletes and strength trainers routinely exceed IBW estimates while carrying very little body fat.
- Age: Older adults may be at lower risk at slightly higher weights. Some studies suggest BMI 25–27 is associated with lower mortality in people over 65.
- Ethnicity: Risk thresholds differ across populations. South Asian and East Asian guidelines often use lower BMI cut-offs (e.g. 23 kg/m² for overweight).
- Body frame size: Small-framed and large-framed individuals have meaningfully different bone mass, affecting healthy weight range.
- Sex assigned at birth: The binary male/female split does not reflect the full range of human physiology.
Better metrics for health
Because IBW is a one-number estimate, it is most useful as a quick clinical reference, not as a personal fitness goal. Consider combining it with these additional measurements:
Frequently asked questions
Which formula is most accurate?
No formula is universally most accurate. Devine is most cited in clinical settings. Robinson tends to be favored for taller individuals. For a personal health goal, the BMI range often gives more useful guidance than any single formula.
Should I aim to reach my IBW?
Not necessarily. IBW formulas were designed for drug dosing, not fitness targets. A healthy body composition — measured by body fat percentage and waist circumference — is a more meaningful goal than a specific scale number.
Why are there different results for men and women?
The formulas reflect average differences in bone density and lean muscle mass between sexes. On average, men carry more lean mass per centimeter of height, which is why the male starting points (50–56 kg) are higher than the female starting points (45–53 kg).
What if I am shorter than 152 cm (5 feet)?
The formulas assume a minimum height of 152 cm. For shorter individuals, they become unreliable. Use BMI range or consult a healthcare professional.
Three established formulas: • Devine (1974): Most widely used in medicine • Robinson (1983): Accounts for body frame • Miller (1983): Generally gives lower estimates The healthy BMI range (18.5–24.9) gives a broader reference range.