Ideal Weight

Comparing Four Published Ideal-Weight Formulas

An “ideal weight” formula estimates a reference body weight from height and gender, using a linear relationship first published decades ago for clinical use. Enter your gender at birth and height, and this calculator shows the result from four different published formulas side by side — plus their average — since no single formula is more “correct” than the others.

Showing all four is deliberate: each was developed independently by a different research group at a different time, and they don’t agree exactly. Presenting just one as a single definitive number would overstate how precise this kind of estimate actually is.

The Formula

Every formula below shares the same shape: a base weight at exactly 5 feet (60 inches) tall, plus a fixed rate for every inch above or below that — so the same one color tracks the same one variable (inches over 5 ft) across all four:

$$\vB{\text{Devine (1974), Men}} = 50.0 + 2.30 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$ $$\vB{\text{Devine (1974), Women}} = 45.5 + 2.30 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$ $$\vC{\text{Robinson (1983), Men}} = 52.0 + 1.90 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$ $$\vC{\text{Robinson (1983), Women}} = 49.0 + 1.70 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$ $$\vD{\text{Miller (1983), Men}} = 56.2 + 1.41 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$ $$\vD{\text{Miller (1983), Women}} = 53.1 + 1.36 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$ $$\vE{\text{Hamwi (1964), Men}} = 48.0 + 2.70 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$ $$\vE{\text{Hamwi (1964), Women}} = 45.5 + 2.20 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$

The Devine formula was originally created for drug-dosing calculations, not general wellness, but is the most widely cited of the four today. Robinson and Miller are both later independent revisions of Devine using updated population data; Hamwi is the oldest, originally a quick bedside estimate for nutrition planning. This calculator’s headline number is the plain average of all four.

Worked Example

A man who is 5’10” (177.8 cm) tall — 10 inches over the 5-foot base:

1. Devine: $50 + 2.3 \times \vA{10} = \vB{73} \text{ kg}$
2. Robinson: $52 + 1.9 \times \vA{10} = \vC{71} \text{ kg}$
3. Miller: $56.2 + 1.41 \times \vA{10} = \vD{70.3} \text{ kg}$
4. Hamwi: $48 + 2.7 \times \vA{10} = \vE{75} \text{ kg}$
5. Average: $(\vB{73} + \vC{71} + \vD{70.3} + \vE{75}) \div 4 = 72.325 \text{ kg}$ (about 159.5 lb).

Key Factors to Consider

• These formulas were originally developed for clinical drug dosing, not personal wellness goals. The Devine formula in particular exists specifically to help calculate accurate medication dosages (which sometimes depend more on lean body mass than total weight) — using the result as a personal weight target stretches these formulas beyond their original clinical purpose.
• Frame size and muscle mass can shift a genuinely healthy weight well outside these formulas’ estimate. A larger-framed or more muscular person can weigh considerably more than these height-only formulas suggest while being entirely healthy — pairing this result with the Body Frame Size or Lean Body Mass calculators gives a fuller picture than height alone.
• None of these formulas account for age, even though healthy weight ranges can shift somewhat with age. All four formulas were derived from adult data without a separate age adjustment — they treat a 25-year-old and a 65-year-old of the same height identically.
• A wide spread between the four formulas’ results is itself informative — it shows the real uncertainty in this kind of estimate. When Devine, Robinson, Miller, and Hamwi disagree by several kilograms for the same height, that spread is a more honest signal of how imprecise “ideal weight” really is than any single number presented alone would be.

Common Mistakes

• Treating the average of the four formulas as a precise personal target. The average is a convenient single number, but it’s still just the midpoint of four independent estimates — not a more accurate figure than any one of them individually.
• Ignoring frame size and muscle mass entirely. These formulas only use height and sex — a muscular or large-framed person can be entirely healthy well outside the estimated range, which is exactly why they’re a reference point, not a goal to chase.
• Applying these formulas to children or teenagers. All four were derived from adult populations — they don’t apply to a still-growing body, which needs pediatric growth charts instead.
• Comparing this result directly against a BMI-based healthy weight range and assuming one is wrong. The two use genuinely different math (BMI incorporates height squared; these formulas are linear), so disagreement between them is expected, not a sign either is broken.

Useful to Know

• Want a body-composition-aware alternative to a height-only formula? The Body Fat Percentage Calculator calculator estimates body fat percentage instead of a single target weight.
• Curious whether your frame is small, medium, or large — a factor these formulas don’t account for? The Body Frame Size Calculator calculator estimates that from wrist circumference.
• Want to see how your actual muscle-vs-fat composition compares, rather than a population average? The Lean Body Mass Calculator calculator estimates that directly.