Compare baseline weight suggestions from Devine, Robinson, Miller, and Hamwi equations alongside clinical healthy BMI boundaries.
A clinical pharmacist calculating drug dosages for a critical care patient must establish their ideal body weight (IBW). Administering weight-dependent drugs based only on total scale weight can lead to dangerous overdosing in obese patients because fat tissue handles drugs differently than active lean mass. Ideal body weight serves as a safer metabolic baseline.
Ideal Body Weight represents a statistical estimation of optimal body mass based on height and gender. Rather than a target weight that accounts for aesthetic desires, IBW is a clinical reference developed to minimize disease risk and optimize health guidelines.
Mathematical equations approximate ideal weight using height as the primary predictor variable. Capping base weight at 5 feet (60 inches) tall, the formulas add or subtract weight for each inch of deviation.
Developed by Dr. Ben Devine, this is the most common equation used in medicine to calculate drug clearance and ventilator tidal volumes.
// Men
IBW = 50.0 kg + 2.3 kg per inch over 5 feet
// Women
IBW = 45.5 kg + 2.3 kg per inch over 5 feetDerived by Robinson, this equation modified Devine's formula based on empirical weight data gathered from general populations.
// Men
IBW = 52.0 kg + 1.9 kg per inch over 5 feet
// Women
IBW = 49.0 kg + 1.7 kg per inch over 5 feetDeveloped by Miller in the same year, this formula uses higher baseline weights but smaller growth increments, typically yielding lower suggestions for taller individuals.
// Men
IBW = 56.2 kg + 1.41 kg per inch over 5 feet
// Women
IBW = 53.1 kg + 1.36 kg per inch over 5 feetThe oldest formula in the collection, the Hamwi equation was created for general nutritional planning and remains popular in dietetics.
// Men
IBW = 48.0 kg + 2.7 kg per inch over 5 feet
// Women
IBW = 45.5 kg + 2.2 kg per inch over 5 feetIBW equations serve critical roles in healthcare:
Ideal weight formulas represent general population averages and are blind to body composition. They do not account for skeletal frame size, muscle mass, or body fat distribution. An athlete or bodybuilder with high muscle mass will naturally weigh significantly more than their calculated "ideal" weight, yet remain in excellent metabolic health. Clinicians combine IBW with BMI and waist circumferences for a complete assessment.
Calculations convert imperial measurements (feet and inches) to inches, then compute deviations from the 60-inch base. For heights under 5 feet, the calculator subtracts weight proportionally (rather than capping at the baseline), ensuring mathematical consistency.
The formulas were developed at different times using different population sets and regression metrics. Devine is the medical standard, while Robinson and Miller represent updated statistical adjustments.
A healthy weight range is defined by the World Health Organization as a BMI between 18.5 and 24.9. This calculator computes these weight boundaries for your height alongside the single-point formulas.
No. These equations are designed for adults aged 18 and older. Pediatric growth is assessed using age-and-gender-specific weight-for-age percentiles from CDC growth charts.
BMI Calculator — Standard weight-to-height screen.
Body Fat Calculator — Estimates body fat using Navy circumference formulas.
Lean Body Mass Calculator — Computes fat-free weight using height and weight formulas.