Ideal Weight Calculator

Estimate your ideal weight range based on historical formulas, biological sex, frame size, and WHO BMI guidelines.

Physique Profiles

Biological Sex

Height Unit

Height (cm)

Body Frame Size

Actual Weight

Weight Unit

Ideal Weight Formulas Comparison

Formula	Ideal (kg)	Ideal (lbs)
Devine (1974)	65.9 kg	145.4 lbs
Robinson (1983)	65.2 kg	143.7 lbs
Miller (1983)	66.0 kg	145.4 lbs
Hamwi (1964)	66.7 kg	147.1 lbs

Average Ideal Weight

65.9 kg

145.4 lbs

WHO Healthy BMI weight range

Lower Limit (BMI 18.5):53.5 kg / 117.9 lbs

Upper Limit (BMI 25.0):72.2 kg / 159.3 lbs

Adjusted Weight (Dosing)

Adjusted Weight:73.6 kg / 162.2 lbs

Actual weight exceeds 120% of IBW. Clinical guidelines suggest using Adjusted Body Weight for specific medication dosing.

Ideal Body Weight & WHO Weight ranges

Ideal Body Weight (IBW) provides a base baseline reference developed for clinical research. The Devine, Robinson, Miller, and Hamwi equations scale weight based on height inches above a 5-foot base.

Body frame sizes adjust formula outcomes by +/- 10%. World Health Organization (WHO) benchmarks set healthy weights within a BMI scale of 18.5 to 25.0. Dosing parameters adjust weight when actual metrics exceed 120% of IBW.

Built and maintained by Meet Shah · Last updated 1 August 2026

What this tool is used for

Comparing the Devine, Robinson, Miller and Hamwi formulas on one height.
Getting a reference figure for a dosing or a clinical calculation.
Seeing how much the formulas disagree with each other.
Producing a number to discuss with a clinician.
Understanding where a common target figure comes from.

Frequently Asked Questions

Where do these formulas come from?: Clinical dosing, not aesthetics. Devine (1974) was published to calculate drug doses and is still used for that; Robinson, Miller and Hamwi are contemporaries with slightly different coefficients. All follow the same shape — a base weight at five feet plus a fixed increment per inch above it.
Why do they only apply above five feet?: Because that is where the linear extrapolation was fitted, and below it the formulas produce implausible results — the base constant dominates and the increment has nothing to subtract from. The tool declines rather than extrapolating into a range the source data never covered.
Which formula is the right one?: None uniquely — they disagree by several kilograms and none was derived as a health target. The average shown is a summary, not a consensus. A BMI-derived healthy range is the better tool for a health question; these are here because clinical protocols still reference them by name.
Does frame size actually change the number?: In the traditional tables, yes — roughly ±10% for small and large frames, usually assessed by wrist circumference or elbow breadth. The evidence base is thin by modern standards, which is why it is offered as an adjustment rather than folded into the base figure.
Why does dosing use ideal rather than actual weight?: Because many drugs distribute into lean tissue rather than fat, so dosing on actual weight over-doses a heavier patient. For patients well above ideal weight, protocols use an adjusted body weight — ideal plus a fraction of the excess — which is why the tool flags when actual exceeds ideal by more than 20%.

Common errors and gotchas

Treating the output as a goal, when these formulas were developed for drug dosing rather than health targets.
Comparing figures across formulas, which can differ by several kilograms for the same height.
Ignoring frame size, muscle mass and body composition entirely, which the formulas do not model.
Applying adult formulas to children, for whom none of them were derived.
Using it as a health assessment rather than a reference number.