Ideal Body Weight Calculator — 4 Medical Formulas

The Formula

Ideal body weight formulas were originally developed for clinical drug dosing, not personal weight targets. Each formula uses a different base weight and adjustment factor for height over 5 feet. The average across all four provides a more reliable reference than any single formula.

Variable Definitions

How to Use This Calculator

1. 1

   Select your unit system (Imperial or Metric).

2. 2

   Select your biological sex.

3. 3

   Enter your height.

4. 4

   Optionally enter your current weight to see how it compares to ideal ranges.

5. 5

   Review all four formulas plus the average — use the range, not a single number.

Common Applications

• Clinical reference — healthcare professionals use the Devine formula for drug dosing calculations (e.g., gentamicin, theophylline) where weight-based dosing is insufficient
• Weight loss goal setting — use the average of all four formulas plus the healthy BMIA weight-for-height index calculated as weight (kg) ÷ height² (m²). Used to screen for weight categories that may indicate health risks. range as an evidence-based reference range rather than fixating on a single number
• Medical nutrition assessment — dietitians reference ideal weight formulas when estimating nutritional needs for patients who cannot be weighed or have significant fluid shifts
• Fitness consultation — compare your current weight against multiple ideal weight formulas to understand the range of clinically normal weights for your height

Ideal weight formulas give different results; use the average and healthy BMI range as references

Understanding the Concept

Ideal body weight is a clinical concept originally designed for medical dosing, not a strict health target. The four formulas (Devine, Robinson, Miller, Hamwi) give different results because they were developed on different populations at different times. For example, the Devine formula tends to give higher values for tall people, while Miller is more conservative. The "ideal" is better understood as a range (the spread between the lowest and highest formula results) rather than a single number. Factors like frame size, muscle mass, age, and ethnicity all affect what weight is healthy for you. The healthy BMIA weight-for-height index calculated as weight (kg) ÷ height² (m²). Used to screen for weight categories that may indicate health risks. range provides an additional reference independent of formula selection. A practical example: a 5'10" male might get ideal weights ranging from 160 lbs (Miller) to 178 lbs (Devine) depending on which formula is used. Neither is "right" or "wrong" — they simply use different assumptions. The average of all four (~169 lbs) is a reasonable reference, but an athlete with high muscle mass might be perfectly healthy at 185 lbs, while someone with a small frame might be healthier at 155 lbs. Rather than fixating on a single "ideal" number, use the BMIA weight-for-height index calculated as weight (kg) ÷ height² (m²). Used to screen for weight categories that may indicate health risks. healthy weight range (18.5–24.9 for your height) as a science-backed target, and assess your body composition, energy levels, and metabolic health markers as more meaningful indicators of health than the number on the scale.

Frequently Asked Questions

Sources & References