Quick answer
Ideal body weight formulas give a weight for a given height and sex: each starts from a base weight at 5 feet and adds a fixed amount per inch above it. The calculator shows four published formulas (Devine, Robinson, Miller and Hamwi) side by side, because none is universally accepted.
These formulas were not designed to predict health, and they only apply from 5 feet (152.4 cm) up. For a weight range based on a health classification, see the weight range in the BMI calculator.
Related tools: Healthy Weight Calculator: Weight range for a normal BMI at your height. BMI Calculator: Find your Body Mass Index (BMI) and weight status.
How to use the Ideal Weight Calculator
- Choose units: Metric (kg, cm) and Imperial (lb, in).
- Choose sex: Male and Female.
- Enter height (cm, or in) (between 50 and 250).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Units | Choose one: Metric (kg, cm); Imperial (lb, in) | Starts at Metric (kg, cm) |
| Sex | Choose one: Male; Female | Starts at Male |
| Height (cm, or in) | A number | ≥ 50, ≤ 250 |
Formula and method
Formula
Devine: 50 (men) / 45.5 (women) kg + 2.3 kg per inch over 5 ft; Robinson, Miller and Hamwi use different constants
IEEE-754 double precision; shown to 1 decimal place unless stated.
Formulas are defined for heights of 5 ft (152.4 cm) and above. They were not derived to predict health outcomes. Informational estimate, not medical advice. Talk to a qualified health professional about your own situation.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Units = Metric (kg, cm); Sex = Male; Height (cm, or in) = 175.
| Result | Value |
|---|---|
| Ideal weight (Devine) | 70.5 kg |
| Robinson | 68.9 kg |
| Miller | 68.7 kg |
| Hamwi | 72 kg |
Example 2
Inputs: Units = Metric (kg, cm); Sex = Female; Height (cm, or in) = 175.
| Result | Value |
|---|---|
| Ideal weight (Devine) | 66 kg |
| Robinson | 64.1 kg |
| Miller | 65.2 kg |
| Hamwi | 65.1 kg |
The first line is the headline result (ideal weight (Devine)). Below it the ideal Weight Calculator lists robinson, miller and hamwi, which describe the same case from other angles. IEEE-754 double precision; shown to 1 decimal place unless stated.
The four formulas (kg, height over 5 ft in inches)
For a man 175 cm tall (68.9 in, 8.9 in over 5 ft): Devine 50 + 2.3 × 8.9 = 70.5 kg, Robinson 52 + 1.9 × 8.9 = 68.9 kg, Miller 56.2 + 1.41 × 8.9 = 68.7 kg and Hamwi 48 + 2.7 × 8.9 = 72.0 kg. The four results differ by about 3 kg, which shows why a single number should not be treated as exact.
| Formula | Men | Women |
|---|---|---|
| Devine | 50 + 2.3 per inch | 45.5 + 2.3 per inch |
| Robinson | 52 + 1.9 per inch | 49 + 1.7 per inch |
| Miller | 56.2 + 1.41 per inch | 53.1 + 1.36 per inch |
| Hamwi | 48 + 2.7 per inch | 45.5 + 2.2 per inch |
Where the formulas come from and why a range is better
The four formulas are decades old: Hamwi (1964), Devine (1974) and Robinson and Miller (both 1983). Some sources describe Devine as originally used to scale drug doses and Robinson as derived from life-insurance tables, but the sources do not agree on every detail, which is another reason not to treat any one of them as a health target.
Modern guidance tends to look at a weight range for a given height instead of a single number. A range based on the adult BMI categories is shown by the BMI calculator, and it gives wider and more realistic limits than any of these four formulas.
Ideal weight for men at different heights
Every figure in this table comes from running this calculator, so it matches what the form returns.
| Height (cm) | Devine (kg) | Robinson | Miller | Hamwi |
|---|---|---|---|---|
| 160 | 56.9 kg | 57.7 kg | 60.4 kg | 56.1 kg |
| 170 | 65.9 kg | 65.2 kg | 66 kg | 66.7 kg |
| 180 | 75 kg | 72.6 kg | 71.5 kg | 77.3 kg |
| 190 | 84 kg | 80.1 kg | 77.1 kg | 88 kg |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Height (cm, or in): entering "150" shows "These formulas apply to heights of 5 ft (152.4 cm) and above." beside that field and no result.
Choosing between the Ideal Weight Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Healthy Weight Calculator](/health/healthy-weight/) | height | Healthy weight range |
| [Adjusted Body Weight Calculator](/health/adjusted-weight/) | sex, actual weight and height | Adjusted body weight |
| [BMI Calculator](/health/bmi-calculator/) | units, weight and height | Your BMI |
| [Height Calculator](/health/height-calculator/) | convert | Height |
| [Body Fat Calculator (U.S. Navy)](/health/body-fat/) | sex, height and neck | Estimated body fat |
Background: body measurements and screening
Body-measurement ratios are screening tools, not diagnoses. BMI ignores body composition and fat distribution, and reviews find waist-to-hip and waist-to-height ratios are useful additions but not clearly better than BMI or waist circumference alone. Where the tape goes matters, so measure at the same sites each time.
Some sources quote a waist-to-hip ratio above 0.8 for women and 0.95 for men as a marker of increased metabolic risk; treat that as a screening flag, and talk to a clinician about what your own numbers mean.
Assumptions and limitations
- Below 5 ft the formulas do not apply
- Not a diagnosis
This calculator gives general information based on published formulas. It is not medical advice, and it cannot account for your health history. Talk to a qualified clinician about decisions that affect your health.
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for height (cm, or in) to confirm this.
Frequently asked questions
Which ideal weight formula is the most accurate?
None is universally accepted, and they were not derived to predict health outcomes. That is why the calculator shows all four.
What does the Ideal Weight Calculator calculate?
Ideal body weight by four published formulas (Devine, Robinson, Miller, Hamwi). It returns Ideal weight (Devine), Robinson, Miller and Hamwi.
What formula does the Ideal Weight Calculator use?
Devine: 50 (men) / 45.5 (women) kg + 2.3 kg per inch over 5 ft; Robinson, Miller and Hamwi use different constants. Formulas are defined for heights of 5 ft (152.4 cm) and above.
What do I need to enter in the ideal Weight Calculator?
You enter Units, Sex and Height (cm, or in).
How is the result rounded or limited?
IEEE-754 double precision; shown to 1 decimal place unless stated. Below 5 ft the formulas do not apply.
What are the limits of this calculator?
Below 5 ft the formulas do not apply. Not a diagnosis.
What does the “Units” option change?
It sets how the ideal Weight is worked out. The choices are Metric (kg, cm) and Imperial (lb, in).
What is an example of a ideal Weight result?
With units Metric (kg, cm), sex Male and height (cm, or in) 175, the ideal weight (Devine) is 70.5 kg.
Where does the method come from?
The method follows: Devine BJ, Drug Intell Clin Pharm 1974;8:650; Robinson JD et al., Am J Hosp Pharm 1983;40:1016; Miller DR et al., Am J Hosp Pharm 1983;40:1622.
Can I rely on this calculator for a decision?
This calculator gives general information based on published formulas. It is not medical advice, and it cannot account for your health history. Talk to a qualified clinician about decisions that affect your health. For this calculator in particular: Below 5 ft the formulas do not apply.
Related calculators
- Healthy Weight Calculator — Weight range for a normal BMI at your height.
- BMI Calculator — Find your Body Mass Index (BMI) and weight status.
- Height Calculator — Convert height between centimeters and feet-and-inches.
- Body Fat Calculator (U.S. Navy) — Estimate body fat percentage from tape measurements (U.S. Navy method).
- Waist-to-Hip Ratio Calculator — Waist-to-hip ratio and WHO risk threshold.
Sources
- Devine BJ, Drug Intell Clin Pharm 1974;8:650
- Robinson JD et al., Am J Hosp Pharm 1983;40:1016
- Miller DR et al., Am J Hosp Pharm 1983;40:1622
- Hamwi GJ, 1964 (Diabetes: Therapy)
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.