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Ideal Weight Calculator

Find your ideal body weight for your height using the Robinson, Miller, Devine and Hamwi formulas, plus the healthy BMI range, in kg or pounds.

61.4 kg / 135.3 lb
Average of the four formulas
53.5–72.3 kg
Healthy range at BMI 18.5–25

Ideal body weight by formula

FormulaIdeal weightWorking
Robinson (1983)60.8 kg / 134.0 lb49 kg + 1.7 kg × 6.93 in over 5 ft
Miller (1983)62.5 kg / 137.8 lb53.1 kg + 1.36 kg × 6.93 in over 5 ft
Devine (1974)61.4 kg / 135.4 lb45.5 kg + 2.3 kg × 6.93 in over 5 ft
Hamwi (1964)60.7 kg / 133.9 lb45.5 kg + 2.2 kg × 6.93 in over 5 ft

None of these were validated as health targets. Devine was created for calculating drug doses and Hamwi was a 1964 bedside rule of thumb — they ignore body composition, frame size, age and ethnicity, and they disagree with one another by several kilograms for the same person. Treat the BMI range as the more defensible reference. Estimates only, not medical advice.

What is the Ideal Weight Calculator?

Ideal body weight formulas estimate a reference weight from height and sex. The Devine formula gives 50 kg for a man of 5 feet plus 2.3 kg per additional inch, and 45.5 kg plus 2.3 kg per inch for a woman.

  • Four formulas — Robinson, Miller, Devine and Hamwi — side by side
  • Healthy BMI 18.5–25 weight range for your height
  • Results shown in kilograms and pounds together
  • Optional current-weight comparison
  • Metric and imperial height input
  • Fully client-side — nothing uploaded, nothing saved

How to use the Ideal Weight Calculator

  1. 1

    Choose metric (cm) or imperial (ft + in) height units.

  2. 2

    Select your sex and enter your height.

  3. 3

    Optionally enter your current weight to see the difference.

  4. 4

    Compare the Robinson, Miller, Devine and Hamwi results.

  5. 5

    Check the healthy BMI weight range for your height.

About the Ideal Weight Calculator

The ByteTools Ideal Weight Calculator gives you a reference weight for your height using the four classic clinical formulas — Robinson, Miller, Devine and Hamwi — side by side, plus the healthy weight range implied by a BMI of 18.5 to 25. Seeing them together makes it obvious that there is no single 'ideal' number.

Enter your height in centimetres or in feet and inches, pick your sex, and optionally add your current weight to see how far each formula sits from where you are today. Results are shown in both kilograms and pounds.

All arithmetic runs locally in your browser and nothing is uploaded or stored. These formulas are rough clinical references, not a target you should chase — they take no account of muscle mass, frame size, age or ethnicity, and they are estimates only, not medical advice. Talk to a doctor about what a healthy weight looks like for you.

Frequently asked questions

What is the Devine formula for ideal body weight?

Devine (1974) gives 50 kg for a man 5 feet tall plus 2.3 kg for each inch above that; for women it is 45.5 kg plus 2.3 kg per inch. A 180 cm man is 10.87 inches over 5 feet, so 50 + 2.3 × 10.87 ≈ 75.0 kg.

Which ideal weight formula is most accurate?

None of them, in the sense you probably mean. Devine was invented for calculating drug doses, not for health targets, and Hamwi was a 1964 bedside rule of thumb for diabetes care. They were never validated as health outcomes targets, they ignore body composition and frame size entirely, and they disagree with each other by 5 kg or more for the same person. Use the healthy BMI range as the more defensible reference.

What is a healthy weight for my height?

The usual reference is the weight range that puts you at a BMI between 18.5 and 25 — for a 170 cm adult that is roughly 53.5 kg to 72 kg. This tool computes that range for your height alongside the four formulas, but BMI itself cannot distinguish muscle from fat.

Does ideal weight depend on age or frame size?

In reality, yes, but these formulas do not model either. Hamwi is sometimes adjusted by ±10% for small or large frames, which is a crude nod to the problem. Body composition, bone structure and age all shift what a healthy weight actually looks like.

Should I try to reach my ideal body weight?

Not as a goal in itself. These are population reference points, not personal prescriptions, and health outcomes correlate far better with fitness, diet quality and body composition than with hitting a specific number. Discuss any weight goal with a healthcare professional.

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