Ideal Weight Calculator - Devine, Robinson, Miller & Hamwi Formulas

How to use this tool

1. Enter your height. Type your height in centimeters or switch to feet and inches.
2. Select sex. Choose male or female (the formulas use sex-specific constants).
3. View formula results. See ideal weight estimates from four clinical formulas.
4. Compare to BMI range. Compare the formula estimates to the BMI-based healthy weight range.

The four ideal weight formulas

All four formulas use height and sex as inputs and were developed empirically from patient population data. They are widely used in clinical medicine for drug dosing, nutritional assessment, and as reference baselines:

• Devine (1974): The most cited formula in pharmacology. Originally created to estimate "ideal" body weight for creatinine clearance calculations in drug dosing.
• Robinson (1983): A revision of Devine that generally produces slightly lower estimates, particularly for taller individuals.
• Miller (1983): Another Devine revision; tends to give the lowest of the four estimates.
• Hamwi (1964): The oldest of the four, developed for dietitian use. Uses a slightly higher per-inch rate for males.

BMI-based healthy weight range

The World Health Organization (WHO) defines a healthy BMI range as 18.5–24.9. For a given height, this translates directly to a weight range using the formula: Weight (kg) = BMI × Height² (m). The healthy weight range shown in this calculator uses these thresholds and does not vary by sex, unlike the IBW formulas.

Body composition vs. weight

Two individuals at the same height and weight can have very different body fat percentages. A competitive powerlifter at 200 lb with 12% body fat has far more muscle and far less fat than a sedentary person at the same weight with 30% body fat. Formula-based ideal weight estimates cannot distinguish between the two. This is why body composition metrics (DEXA scan, bioelectrical impedance) are more clinically informative than weight alone.

Clinical application

Ideal body weight (IBW) formulas are primarily used in pharmacology and clinical care, not as personal fitness goals:

• Drug dosing: renally-cleared medications (aminoglycosides, vancomycin) are dosed on IBW or adjusted body weight rather than total body weight to avoid toxicity in obese patients.
• Mechanical ventilation: tidal volumes in ICU ventilators are calculated per kg of IBW, not actual body weight.
• Nutritional assessment: IBW provides a reference baseline for estimating caloric needs in hospitalized patients.

Use these estimates as a general reference, not a health target. Work with a healthcare provider to establish realistic, individualized goals.

Limitations of ideal weight formulas

No single number captures healthy body weight for all individuals. Limitations include:

• Muscle tissue is denser than fat; athletes and muscular individuals will appear "overweight" by any formula.
• Bone density varies by ethnicity and age.
• These formulas were developed primarily from US and European patient populations.
• They do not account for body composition, waist circumference, or metabolic health.

Use these estimates as a general reference, not a health target. Work with a healthcare provider to establish realistic, individualized goals.