Ideal Weight Calculator – Devine, Robinson & More

Four clinical formulas estimate ideal body weight (IBW) from height and sex. Devine (1974), the medication-dosing standard, adds 2.3 kg per inch above 5 feet to 50 kg for men and 45.5 kg for women. Robinson (1983) uses 52/49 kg with 1.7 kg per inch; Miller (1983) uses 56.5/53.1 kg with 1.41 kg per inch; Hamwi (1964) uses 48/45.5 kg with 2.7 kg per inch. Worked example for a 175 cm (68.9 in) man: Devine = 50 + 2.3×8.9 = 70.5 kg; Robinson gives 67.1 kg, Miller 69.1 kg, Hamwi 72.0 kg. The calculator also converts the healthy BMI band 18.5–24.9 into a weight window for your height — for 175 cm that is 56.7–76.3 kg — which is wider and more realistic than any single formula point.

1. 1

   Enter height and sex

   Provide height in cm or feet/inches and select male or female.

2. 2

   Run all four formulas

   Devine, Robinson, Miller and Hamwi results are computed and displayed side by side.

3. 3

   Show the BMI window

   The healthy 18.5–24.9 kg range for your height is listed as the practical target zone.

• 1

  Treat the 18.5–24.9 BMI window as the real goal; the formula points differ by up to 5 kg.

• 2

  Recalculate after a growth spurt for teenagers, who outgrow static IBW values.

• 3

  Muscular people should sit toward the top of the BMI window, not at formula minimums.

• Chasing one formula number exactly although the four formulas disagree by several kilograms.

• Using IBW for dosing without telling the clinician about high muscle mass or amputations.

• Ignoring frame size: large-framed adults sit naturally near the top of the range.