About the Ideal Weight Calculator
What should you weigh for your height? This ideal weight calculator answers using four established medical formulas — Devine, Robinson, Miller and Hamwi — each developed by researchers as a height-based reference, and shows them side by side. Because the formulas weight height slightly differently, seeing all four gives you an honest range rather than one falsely precise number. Enter your height and sex in metric or imperial units and compare instantly.
Alongside the formula results, the calculator shows the healthy-BMI weight range for your height — the span corresponding to a BMI of 18.5 to 24.9, which is how most health organizations define a normal weight. It's a broader, more forgiving band than any single formula, and often the more useful figure. Treat all of these as reference points: build, muscle mass and age mean healthy weights genuinely differ from person to person.
Features
- Four formulas compared: Devine, Robinson, Miller, Hamwi
- Healthy-BMI weight range for your height
- Metric and imperial input and results
- Separate calculations for men and women
- All results side by side for honest comparison
- Free, instant and nothing stored or shared
How to calculate your ideal body weight
- Choose metric or imperial units.
- Enter your height.
- Select your sex — the formulas differ for men and women.
- Compare the Devine, Robinson, Miller and Hamwi results.
- Check the healthy-BMI range for a broader reference band.
Frequently asked questions
How do the ideal weight formulas work?
Each starts from a base weight at 5 feet and adds a fixed amount per extra inch of height. Devine, for example, gives men 50 kg + 2.3 kg per inch over 5 feet, and women 45.5 kg + 2.3 kg. Robinson, Miller and Hamwi use the same structure with different coefficients, which is why their results differ slightly.
Which formula is the most accurate?
None is 'correct' — all four are simple height-based approximations from mid-20th-century medical research; Devine's was originally created for calculating drug doses. Their spread is the point: if your weight sits within or near the range they define, you're in the territory the formulas consider typical for your height.
Why is my ideal weight different from the BMI range?
The formulas return a single point estimate, while the healthy-BMI range covers every weight producing a BMI of 18.5–24.9 — a deliberately wide band. A formula result normally falls inside that range, but the range better reflects reality: many different weights can be healthy at the same height.
Do these formulas work for very tall or short people?
They're least reliable at the extremes. Built around averages near typical adult heights, they can suggest unrealistically low weights for people under about five feet and questionable values for the very tall. In those cases, the healthy-BMI range is usually the more sensible reference to lean on.
Are these ideal weight numbers medical advice?
No. Ideal-weight formulas and BMI ranges are population-level screening references — they know nothing about your muscle mass, bone structure, body composition or health history. An athlete can be 'overweight' by formula while being extremely fit. Talk to a doctor or dietitian before setting weight goals based on them.