Ideal Weight Calculator
Compares four clinical formulas — Devine, Robinson, Miller, and Hamwi — to estimate ideal body weight by height and sex.
| Formula | kg | lbs |
|---|---|---|
| Devine (1974) | 70.5 | 155.3 |
| Robinson (1983) | 68.9 | 151.9 |
| Miller (1983) | 68.7 | 151.6 |
| Hamwi (1964) | 72.0 | 158.8 |
For informational purposes only. Consult a healthcare professional.
For informational purposes only. Ideal weight is influenced by many individual factors. Consult a healthcare professional.
What Is Ideal Body Weight?
"Ideal body weight" (IBW) is a clinical concept — a reference weight derived from height and sex that was historically used in medicine to calculate medication dosages, estimate nutritional needs, and set ventilator parameters. It originated not from body composition research but from actuarial life insurance tables that correlated certain weight ranges with longer life expectancy.
The term "ideal" can be misleading. These formulas do not represent an aesthetic ideal or a performance optimum — they represent a statistical range associated with average health outcomes in historical population studies. A fit athlete will often weigh more than the "ideal" without any health concern; a person within the "ideal" range can still have unhealthy body fat levels.
The Four Formulas Compared
This calculator computes ideal body weight using four commonly cited clinical formulas. All formulas are based on height in inches; this calculator converts metric heights automatically. The base height of 5 feet (60 inches) is used as the reference, and a weight increment is added for each inch above 5 feet.
| Formula | Year | Male base / increment | Female base / increment |
|---|---|---|---|
| Devine | 1974 | 50 kg + 2.3 kg/in above 60 | 45.5 kg + 2.3 kg/in above 60 |
| Robinson | 1983 | 52 kg + 1.9 kg/in above 60 | 49 kg + 1.7 kg/in above 60 |
| Miller | 1983 | 56.2 kg + 1.41 kg/in above 60 | 53.1 kg + 1.36 kg/in above 60 |
| Hamwi | 1964 | 48 kg + 2.7 kg/in above 60 | 45.5 kg + 2.2 kg/in above 60 |
Worked Example
A 5 ft 10 in (70 inches, 177.8 cm) male has 10 inches above the 60-inch base:
Limitations of Ideal Weight Formulas
All four formulas share important limitations:
- No body composition data: Two people with identical height and sex can have the same IBW estimate but very different muscle-to-fat ratios and health risk profiles.
- Developed from limited populations: The original datasets were predominantly Caucasian American adults. Studies show IBW formulas tend to overestimate ideal weight for Asian populations and may underestimate it for others.
- Does not account for age: Muscle mass naturally declines with age (sarcopenia). An appropriate weight for a 30-year-old may not be the same for a 70-year-old.
- Not validated for extreme heights: At heights below 5 ft or above 6 ft 4 in, the linear formulas become less reliable.
For a more complete picture of your weight relative to your body composition, use this calculator alongside the Body Fat Calculator and the BMI Calculator.
Frequently Asked Questions
Which ideal weight formula is most accurate?
No single formula is universally accurate because "ideal weight" is not a biologically fixed number — it depends on body composition, muscle mass, bone density, age, and health goals. Among the four formulas compared here, Devine (1974) is the most widely cited in clinical and pharmaceutical settings because it is used to calculate drug dosages based on ideal body weight. Robinson (1983) is considered a slight refinement of Devine with better validation data. When the four formulas disagree significantly, treat the range rather than any single value as your target.
How were these ideal weight formulas developed?
All four formulas were derived from population studies conducted in the 1960s–1980s. Devine (1974) published his formula as a tool for calculating drug dosages, not for general weight guidance. Robinson et al. (1983) reanalyzed actuarial data from life insurance tables to develop a revised formula. Miller et al. (1983) used similar actuarial data with a different regression. Hamwi (1964) developed a simple rule-of-thumb formula for clinical use. All were developed from predominantly Caucasian American adult populations, which limits their accuracy for other ethnic groups.
Is my "ideal weight" the same as my goal weight?
Not necessarily. These formulas estimate a statistical ideal based on height and sex — they say nothing about your individual body composition, fitness level, or health history. A competitive powerlifter may weigh significantly more than the formula suggests while being in excellent health, while someone within the formula range but with 35% body fat may have elevated health risks. Use the ideal weight range as a rough reference, not a rigid target. Combine it with body fat percentage (see our Body Fat Calculator) and how you feel and perform, for a more complete picture.
Do these formulas account for age or muscle mass?
No. None of the four formulas use age, activity level, or body composition as inputs — only height and sex. This is a significant limitation. Older adults tend to lose muscle and gain fat, meaning their body weight can stay the same while their health profile deteriorates. Conversely, young athletes who train heavily will typically weigh more than these formulas predict due to higher muscle mass. For older adults especially, body fat percentage is a more meaningful metric than ideal weight.
Why is there a difference between the formula results?
The four formulas were derived from different datasets using different statistical methods, which naturally produces different intercepts and slope coefficients. For a 170 cm (5'7") male, results range from about 68 kg (Devine) to 72 kg (Miller) — a spread of roughly 4 kg. At extreme heights the formulas diverge more significantly. This spread reflects genuine scientific uncertainty about what "ideal" means for a given height, which is why presenting all four together and using the range is more honest than selecting any single number.
Related Calculators
- BMI Calculator — Body Mass Index with WHO weight categories
- Body Fat Calculator — US Navy circumference method
- Calorie Calculator — Daily calorie needs based on size and activity