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Ideal Weight for Height Calculator

HealthHeight, Weight and Growth
Sex
Units
Ideal weight (Devine formula) —
Robinson formula
—
Miller formula
—
Hamwi formula
—
Spread across the four formulas
—
WHO healthy BMI range (18.5–24.9)
—
Ideal weight by formula
The chart appears with your result

Ideal body weight formulas start from a base weight at 5 ft and add a fixed amount per inch above it. The Devine formula, the one most used in clinical dosing, gives men 50 kg plus 2.3 kg per inch and women 45.5 kg plus 2.3 kg per inch. A man of 5 ft 10 in gets 73.0 kg, about 161 lb.

About this tool

Pharmacists, dietitians and people setting a weight goal often want a single reference weight for a given height. This calculator runs the four published ideal body weight equations, Devine, Robinson, Miller and Hamwi, from your height and sex, and puts them next to the weight range that corresponds to a WHO healthy BMI of 18.5 to 24.9. A bar chart compares the four formulas so you can see how far they disagree, which is often 5 kg or more for tall people. The equations were derived from height alone; they ignore frame size, muscle and age, and they were never validated as targets for individual health, so treat them as reference points rather than goals.

How to use it

  1. Choose sex and units

    Each formula has separate male and female constants; pick metric or US feet and inches.

  2. Enter your height

    The Devine result, the three other formulas and the BMI-based range update as you type.

  3. Compare the formulas

    Read the bar chart or the working to see each equation with your height filled in.

Examples

Man, 5 ft 10 in

Sex
Male
Units
US (ft, in, lb)
Height
5
and
10

Result Ideal weight (Devine formula): 160.9 lb
Robinson formula: 156.5 lb
Miller formula: 155.0 lb
Hamwi formula: 165.3 lb
Spread across the four formulas: 155.0 lb – 165.3 lb
WHO healthy BMI range (18.5–24.9): 128.9 lb – 173.5 lb

  1. Height = 70 in, which is 10 in above 5 ft
  2. Devine: 50 + 2.3 × 10 = 73 kg
  3. Robinson: 52 + 1.9 × 10 = 71 kg
  4. Miller: 56.2 + 1.41 × 10 = 70.3 kg
  5. Hamwi: 48 + 2.7 × 10 = 75 kg
  6. WHO BMI 18.5–24.9 at 1.778 m = 58.5 to 78.7 kg

Ten inches above 5 ft adds 23 kg to the Devine base of 50 kg, giving 73 kg or about 161 lb.

Woman, 165 cm

Sex
Female
Units
Metric (cm, kg)
Height
165

Result Ideal weight (Devine formula): 56.9 kg
Robinson formula: 57.4 kg
Miller formula: 59.8 kg
Hamwi formula: 56.4 kg
Spread across the four formulas: 56.4 kg – 59.8 kg
WHO healthy BMI range (18.5–24.9): 50.4 kg – 67.8 kg

  1. Height = 64.96 in, which is 4.96 in above 5 ft
  2. Devine: 45.5 + 2.3 × 4.96 = 56.9 kg
  3. Robinson: 49 + 1.7 × 4.96 = 57.4 kg
  4. Miller: 53.1 + 1.36 × 4.96 = 59.8 kg
  5. Hamwi: 45.5 + 2.2 × 4.96 = 56.4 kg
  6. WHO BMI 18.5–24.9 at 1.65 m = 50.4 to 67.8 kg

165 cm is 64.96 in, so Devine gives 45.5 + 2.3 × 4.96 = 56.9 kg; the other formulas land within about 2 kg.

Woman, 145 cm

Sex
Female
Units
Metric (cm, kg)
Height
145

Result Ideal weight (Devine formula): 38.8 kg
Robinson formula: 44.0 kg
Miller formula: 49.1 kg
Hamwi formula: 39.1 kg
Spread across the four formulas: 38.8 kg – 49.1 kg
WHO healthy BMI range (18.5–24.9): 38.9 kg – 52.4 kg

  1. Height = 57.09 in, which is -2.91 in below 5 ft
  2. Devine: 45.5 + 2.3 × -2.91 = 38.8 kg
  3. Robinson: 49 + 1.7 × -2.91 = 44 kg
  4. Miller: 53.1 + 1.36 × -2.91 = 49.1 kg
  5. Hamwi: 45.5 + 2.2 × -2.91 = 39.1 kg
  6. WHO BMI 18.5–24.9 at 1.45 m = 38.9 to 52.4 kg

Below 5 ft the formulas subtract weight per inch, so the result is an extrapolation and comes with a warning.

How it is calculated

IBW = base weight + kg per inch × (height in inches − 60)

base weight
Devine 50 / 45.5 kg, Robinson 52 / 49 kg, Miller 56.2 / 53.1 kg, Hamwi 48 / 45.5 kg (male / female)
kg per inch
Devine 2.3 / 2.3, Robinson 1.9 / 1.7, Miller 1.41 / 1.36, Hamwi 2.7 / 2.2 (male / female)
height
centimetres are divided by 2.54 to get inches

Each equation is linear in height above 5 ft. Devine published his in 1974 for drug dosing; Robinson and Miller refitted it in 1983 against insurance height-weight tables, and Hamwi's 1964 rule of thumb is the oldest. Results in pounds use 1 lb = 0.45359237 kg. The healthy range solves BMI = weight ÷ height² for weight at BMI 18.5 and 24.9.

Sources

When not to use it

  • For children and teenagers, whose weight is judged against growth charts for age and sex.
  • For very muscular people, where a formula weight can sit well below a healthy body composition.
  • For heights far below 5 ft, where the equations are extrapolated beyond the data they came from.

Common mistakes

  • Treating the Devine number as a precise target when the four formulas can differ by several kilograms.
  • Entering total height in inches in the feet box instead of splitting it into feet and inches.
  • Using the male constants for a woman, which adds about 4.5 kg at every height.

Frequently asked questions

Why do the four formulas give different answers?

They were fitted to different data and eras. Devine chose round numbers for dosing, while Robinson and Miller refitted against life-insurance height-weight tables, so their slopes per inch are smaller. The gap widens with height: at 6 ft 4 in the male results spread over roughly 10 kg.

Which formula do hospitals use?

Devine is the usual choice in clinical pharmacology, for example when dosing aminoglycosides or setting ventilator tidal volume from predicted body weight. That is why it is shown as the headline result here.

How does ideal body weight relate to BMI?

For most adult heights the Devine weight corresponds to a BMI of roughly 21 to 23, inside the WHO healthy band of 18.5 to 24.9. The BMI range shown is wider and reflects a band of acceptable weights rather than one number.

Does frame size change the result?

The original equations ignore frame size. Some clinicians add or subtract about 10 percent for a large or small frame, but that adjustment comes from older practice, not from the published formulas.

Are the formulas valid for older adults?

They take no account of age. Height loss with age lowers the formula weight, while some studies associate slightly higher BMI with lower risk in older people, so the result needs clinical context at older ages.

Is my height saved anywhere?

No. The arithmetic runs in your browser, and the last inputs are kept only on this device until you reset them.

Cite this tool

Using this tool in an assignment, article or report? Copy a citation, or a link for your website.

APA

Tools Directory Editorial Team. (2026, October 9). Ideal Weight for Height Calculator. Tools Directory. Retrieved October 25, 2026, from https://tools.milunir.com/health/height-weight-and-growth/ideal-weight-for-height-calculator/

MLA

Tools Directory Editorial Team. “Ideal Weight for Height Calculator.” Tools Directory, 9 Oct. 2026, https://tools.milunir.com/health/height-weight-and-growth/ideal-weight-for-height-calculator/. Accessed 25 Oct. 2026.

Chicago

Tools Directory Editorial Team. “Ideal Weight for Height Calculator.” Tools Directory. Last modified October 9, 2026. Accessed October 25, 2026. https://tools.milunir.com/health/height-weight-and-growth/ideal-weight-for-height-calculator/.

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