Why "Ideal Weight" Is Complicated

The concept of an ideal body weight has been studied in medicine for over a century. Physicians needed a quick reference for calculating medication dosages based on body size — particularly for drugs where dosing by total body weight would be inaccurate for obese patients. Several formulas were developed, each based on different research populations and mathematical approaches. None of these formulas accounts for body composition, muscle mass, bone density, or individual variation — they are clinical estimation tools, not personal prescriptions.

The Hamwi Formula (1964)

The Hamwi formula was developed by Dr. G.J. Hamwi and published in 1964. For men, the formula starts with 48 kg (106 lbs) for 5 feet of height and adds 2.7 kg (6 lbs) for every inch above 5 feet. For women, it starts with 45.5 kg (100 lbs) and adds 2.2 kg (5 lbs) per inch above 5 feet. For a 5'10" male, the Hamwi ideal weight is 48 + (10 × 2.7) = 75 kg or 166 lbs. The Hamwi formula tends to produce slightly lower estimates than other formulas.

The Devine Formula (1974)

The Devine formula was developed by Dr. B.J. Devine in 1974 for calculating medication dosages and was one of the most widely referenced ideal body weight formulas in clinical medicine for decades. For men: 50 kg + 2.3 kg per inch over 5 feet. For women: 45.5 kg + 2.3 kg per inch over 5 feet. For a 5'10" male: 50 + (10 × 2.3) = 73 kg or 161 lbs. Despite its widespread use in clinical settings, the Devine formula was never validated as an actual ideal weight — it was a practical clinical tool that became widely adopted.

The Miller Formula (1983)

Dr. D.R. Miller's 1983 formula attempted to provide a more generous ideal weight estimate. For men: 56.2 kg + 1.41 kg per inch over 5 feet. For women: 53.1 kg + 1.36 kg per inch over 5 feet. For a 5'10" male: 56.2 + (10 × 1.41) = 70.3 kg or 155 lbs. The Miller formula tends to produce somewhat lower estimates at shorter heights but similar estimates at taller heights compared to other formulas.

The Robinson Formula (1983)

Also developed in 1983, the Robinson formula is another commonly referenced ideal weight equation. For men: 52 kg + 1.9 kg per inch over 5 feet. For women: 49 kg + 1.7 kg per inch over 5 feet. For a 5'10" male: 52 + (10 × 1.9) = 71 kg or 157 lbs. The Robinson formula produces results fairly similar to the Devine formula for most heights.

Which Formula Is Most Accurate?

No single formula is definitively superior for all individuals. All four formulas share the same fundamental limitation — they do not account for body composition. A highly muscular individual will always exceed these ideal weight ranges despite having excellent health. Conversely, someone with very low muscle mass may fall within the ideal weight range while having poor metabolic health. The average of all four formulas provides a reasonable central estimate that smooths out the differences between individual equations.

How to Use Our Free Ideal Weight Calculator

Our free ideal weight calculator at cookiescursor.com calculates your ideal weight using all four formulas simultaneously — Hamwi, Devine, Miller, and Robinson. Enter your gender and height in Imperial or Metric units, and the tool shows all four results in a comparison table along with their average and the healthy BMI weight range for your height. For informational purposes only — consult a healthcare professional for personalized advice. No signup required.

Frequently Asked Questions

Should I try to reach my ideal weight?
These formulas are clinical tools, not personal targets. Focus on health markers — blood pressure, blood glucose, cholesterol, energy levels, and fitness — rather than hitting a specific number from a formula.

Why do the four formulas give different results?
Each formula was derived from different patient populations with different research objectives. The differences reflect the inherent variability in defining a single "ideal" weight.

Do ideal weight formulas account for muscle mass?
No. All four formulas use only height and gender. An athlete with high muscle mass will exceed the formula ranges despite being exceptionally healthy.

Is ideal weight the same as healthy weight?
Not exactly. Healthy weight is typically defined by the BMI range of 18.5 to 24.9. The ideal weight formulas generally fall within this BMI range but not always precisely.

Do these formulas work for children?
No. All four formulas are designed for adults. Pediatric weight assessment uses age and sex-specific growth charts.

What if I am shorter than 5 feet?
The formulas do not include a defined adjustment for heights below 5 feet, where the calculations become less reliable. Consult a healthcare provider for weight assessment at shorter heights.

Calculate Your Ideal Weight Now

Use our free ideal weight calculator to compare all four major formulas. For informational purposes only. No signup required.