Ideal Weight Calculator
This ideal weight calculator shows the weight range that counts as a healthy BMI for your height, and compares four published ideal body weight formulas — Hamwi, Devine, Robinson and Miller — for your height and sex.
Result
Healthy weight range: 122 lb – 164 lb
| CDC healthy BMI range (18.5 to under 25) | 122 lb – 164 lb |
|---|---|
| Hamwi (1964) | 153 lb |
| Devine (1974) | 151 lb |
| Robinson (1983) | 148 lb |
| Miller (1983) | 149 lb |
| Average of the four formulas | 150 lb |
Formulas give one number; the BMI range is the wider span that the CDC classes as a healthy weight.
Healthy Weight vs. “Ideal” Weight
The idea of a single ideal weight comes from formulas written decades ago, mostly to help calculate drug doses. Today, the CDC describes healthy weight for adults as a range: a BMI from 18.5 to less than 25. The calculator shows both, so you can see the range and where the classic formulas fall within it.
The Healthy BMI Range
Rearranging the BMI formula gives the weight at any BMI for a given height:
Weight (lb) = BMI × height (in)² ÷ 703
For 5 ft 8 in (68 in):
- Lower end: 18.5 × 68² ÷ 703 = 121.7 lb
- Upper end: 25 × 68² ÷ 703 = 164.4 lb
The Four Formulas
Each formula starts from a base weight at 5 feet and adds a fixed amount for every inch above that. Results are in kilograms; multiply by 2.2046 for pounds.
| Formula | Men | Women |
|---|---|---|
| Hamwi (1964) | 48 kg + 2.7 kg/in | 45.5 kg + 2.2 kg/in |
| Devine (1974) | 50 kg + 2.3 kg/in | 45.5 kg + 2.3 kg/in |
| Robinson (1983) | 52 kg + 1.9 kg/in | 49 kg + 1.7 kg/in |
| Miller (1983) | 56.2 kg + 1.41 kg/in | 53.1 kg + 1.36 kg/in |
“in” means each inch of height over 5 feet.
Worked Example
A man 5 ft 8 in tall (8 inches over 5 feet):
- Hamwi: 48 + 2.7 × 8 = 69.6 kg = 153.4 lb
- Devine: 50 + 2.3 × 8 = 68.4 kg = 150.8 lb
- Robinson: 52 + 1.9 × 8 = 67.2 kg = 148.2 lb
- Miller: 56.2 + 1.41 × 8 = 67.48 kg = 148.8 lb
- Average of the four: 150.3 lb
- CDC healthy BMI range: 121.7 to 164.4 lb
All four formulas land in the middle of the healthy BMI range at this height. They spread further apart for very tall people, because Hamwi adds the most per inch and Miller the least.
Things to Keep in Mind
A range is more useful than a single number
Bodies vary. Two healthy people of the same height can weigh quite different amounts because of muscle, bone structure and body shape. That’s why the CDC uses a range rather than a single figure.
The formulas weren’t designed as personal goals
Devine’s formula, for example, was published to estimate medication doses. None of the formulas considers age, muscle mass or frame size.
Body composition tells you more
Weight alone can’t separate fat from muscle. The body fat calculator estimates body composition from a few tape measurements, and the BMI calculator shows exactly where a current weight falls.
Talk to a professional about targets
This calculator shows what published formulas and categories give for a height. It doesn’t set a personal goal. A doctor or registered dietitian can help interpret the numbers in the context of your health.
Frequently Asked Questions
What is my ideal weight for my height?
There isn't one single ideal weight. The CDC classes a BMI of 18.5 to less than 25 as a healthy weight for adults, which gives a range. At 5 ft 8 in that range is about 122 to 164 pounds. The classic formulas each give a single number inside or near that range.
What is the Devine formula?
The Devine formula (1974) estimates ideal body weight as 50 kg plus 2.3 kg for every inch over 5 feet for men, and 45.5 kg plus 2.3 kg per inch for women. It was originally developed to help calculate medication doses.
Why do the formulas give different answers?
Each formula was built by different researchers using different data and assumptions. Hamwi (1964), Devine (1974), Robinson (1983) and Miller (1983) use different starting weights and amounts per inch, so their results drift apart for very short or very tall people.
Do the formulas work for people under 5 feet?
The formulas are written in terms of inches over 5 feet, so they weren't designed for shorter heights. Below 5 feet the calculator shows only the CDC healthy BMI range.
Do these formulas account for muscle or body frame?
No. They use only height and sex. They don't consider muscle mass, body frame, age or ethnicity, which is why the healthy BMI range is shown alongside them.
Which number should I use?
The calculator doesn't recommend a target. It shows what the published formulas and the CDC's BMI categories give for your height. A doctor can help interpret these numbers for your own health.
Related Calculators
- BMI CalculatorBody mass index, CDC weight category and healthy weight range.
- Body Fat CalculatorBody fat percentage from tape measurements (U.S. Navy method).
- Calorie CalculatorDaily calories to maintain weight, at four activity levels.
- BMR CalculatorCalories burned at rest, using the Mifflin–St Jeor equation.
Sources
- CDC, Adult BMI Categories — healthy weight is a BMI of 18.5 to less than 25 for adults 20 and older
- Hamwi GJ (1964); men 48 kg + 2.7 kg/in, women 45.5 kg + 2.2 kg/in over 5 ft.
- Devine BJ. Gentamicin therapy. Drug Intelligence and Clinical Pharmacy. 1974;8:650–655.
- Robinson JD, Lupkiewicz SM, Palenik L, et al. Determination of ideal body weight for drug dosage calculations. American Journal of Hospital Pharmacy. 1983;40:1016–1019.
- Miller DR, et al. (1983); men 56.2 kg + 1.41 kg/in, women 53.1 kg + 1.36 kg/in over 5 ft.
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