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By Formula · Hamwi

Hamwi Method Calculator

The Hamwi method (1964) — 106 lb (men) or 100 lb (women) at 5 ft, plus 6 lb or 5 lb per inch — is the dietitian's rule of thumb. It is pre-selected below; enter your height and sex.

Find Your Ideal Weight

Required: the ideal-weight formulas use biological sex (male or female) as a variable, so the estimate can’t be calculated without it.

Age adjusts the healthy BMI reference range for adults 65+ (senior guidelines use BMI 23–28).

cmft·in
cm

Enter your height in centimeters (e.g., 170 cm)

Valid range: 152–214 cm (approx. 5 ft – 7 ft)

The ±10% frame adjustment is applied to all four formulas. Clinical medication dosing uses the unadjusted medium-frame value.

Women (>165 cm): Small <15.9 cm · Medium 15.9–16.5 cm · Large >16.5 cm
Valid range: 10–30 cm

Displays the average across all four major clinical formulas for a balanced target.

*This calculator is for informational purposes only. Please consult a healthcare professional before making any health decisions. See our medical disclaimer for more information.

Calculations are powered by the Devine, Robinson, Miller & Hamwi IBW Equations, four peer-reviewed clinical formulas for ideal body weight validated for adult assessment (Pai & Paloucek, Ann Pharmacother, 2000).

Quick Answer

The Hamwi Method

The Hamwi method (1964) is 106 lb (men) or 100 lb (women) at 5 ft, plus 6 lb or 5 lb per inch above that. For a 5 ft 8 in man that is 154 lb (69.9 kg). Enter your height above with Hamwi pre-selected as the primary formula.

How the Hamwi Calculation Works

Hamwi was designed to be done in your head at the bedside. Start from 106 lb for a man or 100 lb for a woman at 5 ft, then add 6 lb (men) or 5 lb (women) for each inch of height above that. A 6-foot man is 12 inches over, so Hamwi gives 106 + (6 × 12) = 178 lb, about 80.7 kg. The calculator converts these pounds into kilograms automatically — internally it uses the metric equivalents of about 48.1 kg plus 2.72 kg per inch for men, and 45.4 kg plus 2.27 kg per inch for women. Like every ideal-weight formula, it takes only height and sex; it says nothing about your body composition, so the healthy BMI range is shown alongside it.

Hamwi Against the Other Formulas

Because it has the steepest slope, Hamwi is the highest of the four at average and above-average heights and near the bottom at very short statures, where the shallower Miller takes the top spot. Treat Hamwi as the generous end of the range rather than the definitive answer, and let the average smooth it against Devine, Robinson and Miller. To see how much lean tissue underlies your own weight, use the Lean Body Mass Calculator, and to place a Hamwi figure on the standard scale, the BMI Calculator shows the band for your height. Compare all four at once in the Ideal Weight Calculator.

Hamwi, G.J. (1964), described in Pai & Paloucek, 2000. The method is a population-based reference, not medical advice, and does not account for muscle mass or individual health conditions.

Frequently Asked Questions

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