"How much should I weigh?" is one of the most common health questions people ask — and one of the hardest to answer with a single number. Your ideal weight depends on a complex interplay of height, age, sex, muscle mass, bone structure, and personal health goals. Yet several mathematical formulas have been developed over the past century to provide useful starting estimates.
In this guide, we will compare the four most widely used ideal body weight (IBW) formulas — Devine, Robinson, Miller, and Hamwi — examine their origins and strengths, and help you understand which one might be most appropriate for your situation.
Before diving into the formulas, it is important to acknowledge a fundamental truth: there is no single "ideal" weight for any given height. The concept of ideal body weight was originally developed for clinical purposes — specifically for calculating drug dosages in hospital settings. It was never intended to serve as a personal fitness target.
That said, IBW formulas provide a useful reference point. When you see estimates from multiple formulas, the range they produce can give you a reasonable ballpark for a healthy weight target. Think of these formulas as guideposts, not destinations.
Developed by Dr. B.J. Devine, this is the most widely used IBW formula in clinical settings. It was originally created for calculating medication dosages and has since become the default in many medical calculators and pharmacy references.
Best for: Clinical and pharmaceutical use; general population estimates
Limitation: Tends to underestimate ideal weight for taller individuals and does not account for age or body frame
Dr. J.D. Robinson modified the Devine formula to produce slightly lower estimates, arguing that the original Devine values were too high for most people.
Best for: People with smaller body frames; those who find the Devine estimate too high
Limitation: May underestimate for larger-framed or more muscular individuals
Dr. D.R. Miller proposed a formula that uses a different baseline and a lower increment per inch, resulting in generally lower estimates than both Devine and Robinson.
Best for: Shorter individuals; those seeking a more conservative weight target
Limitation: Can produce unrealistically low estimates for very tall people
Dr. G.J. Hamwi developed this formula for clinical dosage calculations. It uses pounds and inches, with a different baseline and increment structure than the metric-based formulas.
Best for: Taller individuals; those with larger body frames; people who prefer a more generous estimate
Limitation: May overestimate for shorter people and smaller frames
Let us compare all four formulas for a 5'10" (178 cm) man and a 5'5" (165 cm) woman:
| Formula | Men (5'10") | Women (5'5") |
|---|---|---|
| Devine | 73.9 kg (163 lbs) | 57.6 kg (127 lbs) |
| Robinson | 70.8 kg (156 lbs) | 56.4 kg (124 lbs) |
| Miller | 68.1 kg (150 lbs) | 55.8 kg (123 lbs) |
| Hamwi | 78.6 kg (173 lbs) | 57.7 kg (127 lbs) |
The answer depends on your specific situation:
Several of these formulas can be adjusted for body frame size, which significantly impacts ideal weight:
You can estimate your frame size by measuring your wrist circumference:
| Height | Small Frame (Women) | Medium Frame (Women) | Small Frame (Men) | Medium Frame (Men) |
|---|---|---|---|---|
| Under 5'5" | <5.5" wrist | 5.5–5.75" wrist | — | — |
| 5'5"–5'10" | <6" wrist | 6–6.25" wrist | <6.5" wrist | 6.5–7.5" wrist |
| Over 5'10" | — | — | <7" wrist | 7–8" wrist |
None of the traditional IBW formulas account for age, but research suggests that ideal weight increases modestly with age. A commonly cited guideline suggests adding 1 kg for each decade over age 25. This reflects the natural increase in body fat and decrease in muscle mass that occurs with aging, though regular exercise can significantly mitigate these changes.
Instead of fixating on a single "ideal" number, consider using a healthy weight range based on BMI. For adults, a BMI between 18.5 and 24.9 is generally considered healthy. You can convert this to a weight range using your height:
For our 5'10" (1.78 m) man: 58.6 kg (129 lbs) to 78.9 kg (174 lbs). This range naturally encompasses most IBW formula estimates.
Ideal body weight formulas are useful reference tools, but they should never be treated as gospel. The best approach is to calculate your estimate using multiple formulas, consider your frame size and age, and then focus on the habits that actually matter: regular exercise, balanced nutrition, adequate sleep, and stress management. How you feel, perform, and what your health markers say matter far more than what any formula calculates.
Compare all four IBW formulas instantly with our free ideal weight calculator. See your personalized range in both metric and imperial units.
Try the Ideal Weight Calculator →Disclaimer: This article is for informational purposes only and does not constitute medical advice. Consult a healthcare provider for personalized weight management guidance. Last updated: April 2026.