Ideal body weight calculator
There is no single ideal weight. Five clinical formulas are shown together here, because seeing them disagree is more honest than picking one.
- Robinson formula
- 68.9
- Miller formula
- 68.7
- Hamwi formula
- 72.0
- Broca index
- 67.5
- Healthy BMI range, lower
- 56.7
- Healthy BMI range, upper
- 76.3
Show the working
- Height = 175
- Sex = 1
- inches_over_5ft = 175 / 2.54 - 60 = 8.897 64
- Devine formula = 1 > 0 ? 50 + 2.3*8.897 64 : 45.5 + 2.3*8.897 64 = 70.4646
- Robinson formula = 1 > 0 ? 52 + 1.9*8.897 64 : 49 + 1.7*8.897 64 = 68.9055
- Miller formula = 1 > 0 ? 56.2 + 1.41*8.897 64 : 53.1 + 1.36*8.897 64 = 68.7457
- Hamwi formula = 1 > 0 ? 48 + 2.7*8.897 64 : 45.5 + 2.2*8.897 64 = 72.0236
- Broca index = 1 > 0 ? (175 - 100) * 0.9 : (175 - 100) * 0.85 = 67.5
- Healthy BMI range, lower = 18.5 * (175/100)^2 = 56.6563
- Healthy BMI range, upper = 24.9 * (175/100)^2 = 76.2563
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
Scenarios & local history
Compare a saved scenario
Recent calculations
The formula
- Devine, men: 50 kg + 2.3 kg per inch over 5 feet
- Robinson, men: 52 kg + 1.9 kg per inch over 5 feet
- Miller, men: 56.2 kg + 1.41 kg per inch over 5 feet
- Hamwi, men: 48 kg + 2.7 kg per inch over 5 feet
- Broca, men: (height in cm - 100) x 0.9
The Devine formula was invented in 1974 to scale drug doses, not to describe health. It is still the one most often used in clinical dosing.
Below 5 feet all of these extrapolate into nonsense, because they are linear fits anchored at 60 inches.
This is a population formula, not a diagnosis. Individual metabolism, body composition and medical history all move the real answer, so treat the number as a starting point and talk to a clinician about anything that matters.