Ideal Weight Calculator
Enter your height and sex to compare four ideal body weight formulas alongside the BMI-based healthy range.
Enter a height between 122 cm (4 ft) and 244 cm (8 ft) to compare ideal weight estimates.
Estimates only — not medical advice. Calculated on your device; nothing is sent anywhere.
How it works
- Choose metric (cm) or imperial (feet and inches) units and select your sex.
- Enter your height — all results update live as you type.
- Compare the Robinson, Miller, Devine, and Hamwi estimates with the BMI healthy range shown below them.
Frequently asked questions
- How do the four ideal weight formulas work?
- Each formula starts from a base weight at 5 feet of height and adds a fixed amount per additional inch. Devine (1974) uses 50 kg + 2.3 kg per inch for men; Robinson (1983) and Miller (1983) revised those coefficients using later population data; Hamwi (1964) was originally a quick bedside rule for clinicians. All four take only height and sex as inputs.
- Why do the formulas give different answers?
- They were derived by different authors in different decades from different reference populations, so their base weights and per-inch increments disagree. A spread of 3 to 6 kilograms between the highest and lowest estimate is completely normal. That spread is exactly why this calculator shows all four side by side instead of presenting one number as the truth.
- Which result should I trust — a formula or the BMI range?
- The BMI-based healthy range is generally the more useful reference, because it defines a span of weights (BMI 18.5 to 24.9) rather than a single target and is what health services use for screening. The named formulas remain common in clinical drug dosing and as historical benchmarks. If your weight falls inside the BMI range, being above or below a specific formula value carries little meaning.
- Do these formulas account for muscle mass, age, or frame size?
- No. They use only height and sex, so a muscular athlete and a sedentary person of identical height get identical targets. None of the formulas adjust for age, bone structure, or body composition, which is a known limitation. For individual guidance, body fat percentage, waist circumference, or a clinician’s assessment are far more informative than any height-based estimate.
- Is my height or sex stored or sent anywhere?
- No. Every calculation runs entirely in your browser with no network requests, so nothing you enter is uploaded, logged, or saved. The page keeps working even if you go offline after it loads, and closing the tab leaves no trace of your inputs.
About this tool
This ideal weight calculator takes your height and sex and returns estimates from the four formulas most often cited in medicine — Robinson (1983), Miller (1983), Devine (1974), and Hamwi (1964) — together with the healthy weight range implied by a BMI of 18.5 to 24.9. Results appear as a small comparison list in kilograms or pounds, updating live as you type, with no signup and nothing to install.
All four formulas share the same structure: a base weight assigned at 5 feet of height plus a fixed increment for every inch above it, with separate coefficients for men and women. Devine’s version was created to standardize drug dosing and is still used for that purpose today; Robinson and Miller later refitted the coefficients against actuarial data; Hamwi’s rule predates them all as a quick clinical shortcut. The calculator converts your height to inches internally, applies each formula, and converts the output to your chosen unit. Everything runs client-side in your browser — height and sex are health data, and no network request ever carries them off your device.
The practical takeaway is that ranges matter more than any single number. The four formulas typically disagree by several kilograms for the same person, and none of them consider muscle mass, age, or frame size. The BMI-based range shown beneath them is the reference most health services actually use for screening, precisely because it acknowledges that a span of weights is compatible with good health at any given height.
Typical uses include sanity-checking a weight goal before starting a training or nutrition plan, understanding the ideal body weight figure a clinician or pharmacist mentioned, and seeing how the historical formulas compare with the modern BMI approach. A practical tip: aim for somewhere inside the BMI range that feels sustainable for you, and treat the formula values as context rather than targets — a difference of a few kilograms between them has no clinical significance for a healthy adult.