Ideal Weight Calculator
Four formulas, four answers, all of them defensible. They were written for drug dosing rather than for aesthetics, and the spread between them is the honest part.
How the math works
All four start from 5 ft and add weight per inch above it, in kilograms. Devine: 50 kg male or 45.5 female, plus 2.3 per inch. Hamwi: 48 or 45.5, plus 2.7 or 2.2. Robinson: 52 or 49, plus 1.9 or 1.7. Miller: 56.2 or 53.1, plus 1.41 or 1.36. Frame size adjusts the result by 10 percent either way.
Common questions
- Which ideal weight formula is right?
- None of them exactly. They were built for clinical dosing, not for goal setting, and they disagree by 15 to 20 pounds at the same height. Treat the spread as the answer, and the healthy BMI range as the wider truth.
- Why do these formulas ignore muscle?
- Because they use only height and sex. A muscular person will read as above their ideal weight while being perfectly healthy. Body fat percentage is far more informative, which is why a tape measure often beats a scale.
- How do I measure my frame size?
- Wrap your thumb and middle finger around the opposite wrist. If they overlap, your frame is small; if they just touch, medium; if they do not meet, large. It is crude but it is the standard method.