Ideal Weight Calculator
Find your ideal body weight by height and sex using the Devine, Robinson and Hamwi formulas, alongside the healthy BMI weight range.
The formulas
All take height in inches over 5 feet (h) and return kilograms:
- Devine (1974): men 50 + 2.3·h, women 45.5 + 2.3·h — the standard used in medicine for dosing.
- Robinson (1983): men 52 + 1.9·h, women 49 + 1.7·h.
- Hamwi (1964): men 48 + 2.7·h, women 45.5 + 2.2·h.
- Healthy BMI range: 18.5–24.9 × height² (m) — the evidence-based band rather than a point value.
Worked example
A man of 170 cm (5′7″): h = 7 inches over 5 feet.
Devine 50 + 2.3×7 = 66.1 kg; Robinson 52 + 1.9×7 = 65.3 kg;
Hamwi 48 + 2.7×7 = 66.9 kg. Healthy BMI range: 53.5–72.0 kg.
The three formulas agree within 1.6 kg — all comfortably inside the BMI band.
How to use these numbers
Treat the formula values as reference points, not targets. If your goal weight is inside the healthy-BMI range and
sustainable for you, it's a reasonable goal; the exact kilogram matters far less than body composition and habits.
Frequently asked questions
Which ideal weight formula is best?
None is "best" — Devine (1974) is the medical standard for drug dosing, Robinson and Hamwi are refinements from similar research. They agree within a few kilograms for most heights. The healthy-BMI range is the broadest, evidence-based guide.
Why is my ideal weight a range, not one number?
Because healthy weight genuinely varies with frame size, muscle mass and body composition. Anywhere inside the BMI 18.5–24.9 range for your height is considered healthy — the formula values are just reference points inside it.
Do these formulas work for short people?
The classic formulas are defined from 5 feet (152.4 cm) upward; below that they extrapolate poorly, so we show the healthy-BMI range instead, which works at any adult height.
Do men and women have different ideal weights?
Yes — at the same height the formulas assign women roughly 2–5 kg less, reflecting average differences in build. Individual variation is larger than that difference, so treat the numbers as guides.
This tool provides general health information, not medical advice. Consult a healthcare professional before making decisions based on it.