Ideal Weight Calculator

ideal body weight = base weight + (height in inches − 60) × kilograms per inch

height

Height above 5 feet (60 inches), in inches (in)

base weight

Weight at exactly 5 feet: 50.0 kg for men and 45.5 kg for women on Devine; 52.0 / 49.0 on Robinson; 56.2 / 53.1 on Miller (kg)

kilograms per inch

Slope of the line: 2.3 for both sexes on Devine, 1.9 for men and 1.7 for women on Robinson, 1.41 and 1.36 on Miller (kg)

Use the Devine formula when you need a single number to scale a drug dose, which is what all three were fitted for; Devine is the one most dosing references print. For a health target, read the healthy weight range instead — that range is the one public health bodies publish. The two height and weight tables below print every value the formulas produce, so you can check a number without typing it in.

1. A man 175 cm tall

   1. Convert to inches: 175 ÷ 2.54 = 68.9 inches
   2. Subtract the 60-inch base: 68.9 − 60 = 8.9 inches above 5 feet
   3. Devine: 50.0 + 8.9 × 2.3 = 70.5 kg
   4. Robinson: 52.0 + 8.9 × 1.9 = 68.9 kg
   5. Miller: 56.2 + 8.9 × 1.41 = 68.7 kg

   The three answers span 1.8 kg. That spread, not any single number, is what these formulas actually tell you.

2. A woman 163 cm tall

   1. 163 ÷ 2.54 = 64.2 inches, so 4.2 inches above the base
   2. Devine: 45.5 + 4.2 × 2.3 = 55.1 kg
   3. Robinson: 49.0 + 4.2 × 1.7 = 56.1 kg
   4. Miller: 53.1 + 4.2 × 1.36 = 58.8 kg

   Devine starts 4.5 kg lower for women and keeps the same slope, so that gap never changes. Robinson and Miller start lower too, but with shallower slopes — their gap widens as height increases.

3. A man exactly 152.4 cm tall

   1. 152.4 cm is exactly 60 inches — five feet
   2. The per-inch term is zero, so each formula returns its base weight
   3. Devine 50.0 kg, Robinson 52.0 kg, Miller 56.2 kg

   At exactly five feet the slope drops out. Below it the calculator holds these values rather than extrapolating downward.

The three formulas were derived for drug dosing, not for health, and none of them accounts for frame size, muscle mass or age: a 175 cm athlete and a 175 cm sedentary adult get the same answer. Devine was fitted to a small 1974 sample and has never been validated against measured body composition. Robinson and Miller regress on Metropolitan Life tables, which were insured-population averages, and the published coefficients are rounded differently by different sources. Below five feet (152.4 cm) the formulas would extrapolate downward into the underweight BMI range, so the calculator holds the five-foot value instead. No result here applies during pregnancy.

What is ideal body weight?

Ideal body weight is a number computed from height and sex rather than a measured target. Devine, Robinson and Miller each define it differently, and at adult heights they disagree by one or two kilograms. The formulas exist because drug doses are often scaled to body size and a bedside measurement of body composition is not available.

Why do the Robinson formula and the Miller formula give different numbers?

They regress different data. Robinson fits the combined frame sizes of the 1959 Metropolitan Life tables; Miller fits later Metropolitan Life tables and comes out with a higher base weight and a shallower slope. Neither is more correct — they summarize slightly different populations, and both are averages, not recommendations.

Which ideal body weight formula do doctors use?

Devine, by a wide margin, and it is the one this calculator shows first. It is also the simplest of the three: 50.0 kg plus 2.3 kg for every inch over five feet for men, 45.5 kg plus the same 2.3 kg per inch for women. Because both sexes share the slope, women read exactly 4.5 kg lower at every height.

Does ideal body weight work for athletes and muscular people?

No. Every formula here uses height and sex only, so a heavily muscled adult is told to weigh the same as anyone else of that height. If you train seriously, a body fat measurement or the BMI healthy weight range will describe you better than an ideal weight formula does.

Is the healthy weight range the same thing as ideal body weight?

No, and the difference matters. The healthy weight range is the interval that keeps you inside the normal BMI band at your height — a range built from population risk, which is why it is what public health guidance publishes. An ideal body weight is a single number from a dosing formula. When the two disagree, the range is the one to read as health advice.

What happens below 152.4 cm, where the formulas were not fitted?

The three formulas are anchored on five feet, which is also the shortest height they were fitted over, so below it they extrapolate. The calculator accepts heights down to 120 cm but holds the five-foot value all the way: a 140 cm man reads exactly the numbers a 152.4 cm man reads — 50.0, 52.0 and 56.2 kg — instead of values that carry on falling. That is a stop, not a correction. Left to extrapolate, Devine would hand a 140 cm woman 34.3 kg, below the 36.3 kg that BMI 18.5 marks as underweight at her height, so her ideal weight would land inside the underweight band. Below five feet, BMI or a body-fat measurement is the better guide.

• Determination of ideal body weight for drug dosage calculations — American Journal of Hospital Pharmacy, 1983 (Robinson et al.)
• Body Mass Index (BMI) — healthy weight — US Centers for Disease Control and Prevention
• Obesity: preventing and managing the global epidemic (WHO Technical Report Series 894) — World Health Organization