Healthy Weight Calculator
What weight range is considered healthy for your height? This calculator converts the CDC/WHO healthy BMI band (18.5–24.9) into pounds or kilograms for your height, and lines it up against four classic ideal-weight formulas — Devine, Robinson, Miller, and Hamwi — so you can see the honest spread. Add your current weight to see where you sit.
How you compare
A healthy weight is a band, not a bullseye
Public-health bodies define healthy weight through BMI: weight (kg) divided by height (m) squared, with 18.5–24.9 considered the healthy band for adults. Converting that band back to pounds gives a surprisingly wide range — about 44 lb wide for someone 5′9″. The four ideal-weight formulas shown were mostly invented for medication dosing between 1964 and 1983, and each lands at a slightly different point in or near the band. None of them can see your muscle mass, bone structure, or where you carry fat, which is why waist size and body-fat percentage are better second opinions than any single target weight.
How it’s calculated
BMI range: weight = BMI × height², evaluated at 18.5 and 24.9 kg/m² (CDC/WHO adult bands). Formulas (kg, using inches over 5 ft): Devine = 50 (M) / 45.5 (F) + 2.3 per inch; Robinson = 52/49 + 1.9/1.7; Miller = 56.2/53.1 + 1.41/1.36; Hamwi = 48/45.5 + 2.7/2.2. Your BMI = weight ÷ height².
General educational estimates, not medical advice or a diagnosis. BMI and ideal-weight formulas ignore body composition and do not apply in pregnancy or under age 18 — discuss weight goals with a clinician or registered dietitian.
Worked example
A 5′9″ 30-year-old man: healthy BMI range 125–169 lb (56.8–76.5 kg). The formulas cluster inside it — Devine 156 lb (70.7 kg), Robinson 152 lb, Miller 152 lb, Hamwi 159 lb. If he currently weighs 160 lb, his BMI is 23.6, inside the healthy band.
Common mistakes
- Treating one formula’s output as “the” ideal weight — the four estimates span roughly 7 lb even for an average height.
- Applying adult BMI bands to teenagers; under 18, growth charts and percentiles apply instead.
- Ignoring composition: gaining muscle can raise BMI while health improves.
- Crash-dieting to the bottom of the range; the low end is not healthier than the middle for most people.
Where it is used
- Setting a realistic goal-weight range before a diet or training block.
- Clinical drug dosing (Devine ideal body weight is still used for some medications).
- Insurance and occupational health screenings that reference BMI bands.
- Sanity-checking weight-loss app targets.
Frequently asked questions
Why do the four ideal-weight formulas disagree?
Each was fit to a different purpose and population — Hamwi (1964) and Devine (1974) were built for drug dosing, Robinson and Miller (1983) re-fit the idea to newer data. They can differ by 5–10 lb for the same person, which is a good reminder that ideal weight is an estimate band, not a precise target.
Is the healthy BMI range valid for everyone?
No. BMI ignores body composition, so muscular people can sit above 24.9 while lean, and some people inside the range can carry excess visceral fat. It is designed for adults 18+, and does not apply during pregnancy. Use waist measurements and body-fat estimates alongside it.
Does age change what a healthy weight is?
The CDC healthy BMI range (18.5–24.9) is the same for all adults, but several studies in adults over 65 associate the lowest mortality with BMIs modestly above that band, roughly 23–28. For older adults, preserving muscle usually matters more than chasing the low end of the range.
Should I aim for the formula weight or the BMI range?
Treat the BMI range as the evidence-based band and the formulas as historical midpoints inside or near it. A realistic target is any weight inside the range that you can maintain with habits you enjoy — health markers like blood pressure, lipids, and fitness matter more than a single scale number.
What about frame size?
Classic tables adjusted roughly ±10% for large or small frames (often judged by wrist or elbow breadth). That adjustment is folklore more than science, but it is a reasonable reminder that a healthy weight is a personal range, not one number.