Ideal Weight Calculator
See your ideal weight from the Devine formula (1975) and the healthy BMI band (18.5–24.9) for your height, shown in kg or pounds.
Devine formula (1975): 50 kg + 2.3 kg per inch over 5 ft for men, 45.5 kg + 2.3 kg per inch for women — originally derived for drug dosing and still the most-cited ideal-weight equation. The healthy band multiplies your height in meters squared by BMI 18.5 and 24.9 (WHO limits). Imperial results are converted from kilograms.
This tool runs entirely in your browser. Your data never leaves your device — it is not uploaded to any server.
How to use
- 1Choose metric (cm) or imperial (ft + in) units.
- 2Enter your height.
- 3Compare the Devine estimates for men and women with the healthy BMI band.
- 4Use the range, not one number, when you set a weight goal.
Ideal Weight Calculator
This calculator shows two complementary answers. The Devine formula (1975) — 50 kg + 2.3 kg per inch over 5 ft for men, 45.5 kg + 2.3 kg per inch for women — was originally derived to dose drugs like digoxin and is still the most-cited ideal-weight equation in medicine. The healthy BMI band multiplies your height in meters squared by 18.5 and 24.9, the WHO's normal-range limits.
Enter your height in centimeters or feet and inches. The two methods usually disagree by a few kilograms, which is exactly the point: a single ideal weight does not exist. Treat both numbers as a frame of reference around a healthy range, not a target to force yourself into — the estimate is not medical advice.
Frequently asked questions
Where does the Devine formula come from?
Dr. B. J. Devine published it in 1975 as a quick way to estimate drug dosing weights from height: 50 kg for the first 5 feet plus 2.3 kg per additional inch for men, 45.5 kg for women. It was never designed as a beauty or fitness target, which is why the WHO-based BMI band is shown next to it.
Why is the answer a range instead of one number?
Because healthy weight depends on frame, muscle mass, age and ethnicity, no single number fits. The band 18.5–24.9 × height² comes from the WHO BMI classification and covers the weights research links with the lowest overall risk for most adults.
Is this medical advice?
No — this is an estimate, not medical advice. Athletes and very muscular people sit above the band while perfectly healthy, and some conditions shift the healthy range. Discuss a target weight with a healthcare professional.
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