Ideal Weight Calculator (2026)
Ask five different medical formulas what you "should" weigh and you'll get five different answers - because there is no single ideal weight, only several methods built for different purposes over the last century. This calculator runs your height and sex through all five recognized formulas at once - Devine, Robinson, Miller, Hamwi, and the healthy BMI range - so you see the full picture instead of one number presented as gospel.
| Method | Result |
|---|
What "Ideal Weight" Actually Means
"Ideal body weight" is not one scientifically fixed number - it's a term used across several different formulas developed at different times, for different clinical reasons, using different research populations. Some, like the Devine formula, were built to standardize drug dosage calculations in hospitals, not to hand out as a personal fitness goal. Understanding this history is the key to using these calculators correctly: they're reference points and a useful range, not a target you must hit exactly.
- No single formula is the definitive "correct" ideal weight
- Devine, Robinson, Miller, and Hamwi are all height-and-sex-only formulas
- Results between formulas commonly differ by 5 to 10 lb (2 to 5 kg) for the same height
- The Devine formula was originally created for medication dosing, not general wellness
- The healthy BMI range method is the most current, widely endorsed alternative
- None of the five formulas directly measure muscle mass or body fat
The Five Formulas Explained
All height-based formulas below use the same core pattern: a base weight for exactly 5 feet of height, plus an addition for every inch taller. This calculator applies all five automatically:
Devine (1974) — Men: 50 kg + 2.3 kg/inch over 5ft | Women: 45.5 kg + 2.3 kg/inch over 5ft
Robinson (1983) — Men: 52 kg + 1.9 kg/inch over 5ft | Women: 49 kg + 1.7 kg/inch over 5ft
Miller (1983) — Men: 56.2 kg + 1.41 kg/inch over 5ft | Women: 53.1 kg + 1.36 kg/inch over 5ft
Hamwi (1964) — Men: 48 kg + 2.7 kg/inch over 5ft | Women: 45.4 kg + 2.2 kg/inch over 5ft
Healthy BMI Range — Weight = BMI(18.5 to 24.9) × Height(m)²
The Devine, Robinson, Miller, and Hamwi formulas are all "0 below 5 feet" style equations - if someone is shorter than 5 feet, most clinical calculators subtract instead of add per inch, which this calculator also applies correctly. The healthy BMI range method works differently: rather than one number, it produces a lower and upper healthy weight bound for your exact height.
Formula Comparison Table
Illustrative results for a man at 5'9" (175 cm) with a medium frame:
| Method | Origin / Purpose | Approx. Result |
|---|---|---|
| Devine (1974) | Medication dosing standard | ~72.7 kg (160 lb) |
| Robinson (1983) | Refinement of Devine | ~69.1 kg (152 lb) |
| Miller (1983) | Refinement of Devine/Robinson | ~69.9 kg (154 lb) |
| Hamwi (1964) | Original quick clinical estimate | ~72.3 kg (159 lb) |
| Healthy BMI Range | Modern population health standard | 66.4 – 89.5 kg (146 – 197 lb) range |
Notice the four classic formulas cluster fairly closely together (roughly 69–73 kg), while the healthy BMI range gives a much wider - and arguably more realistic - acceptable band, since a healthy weight genuinely varies with body composition, not just height.
Body Frame Size Adjustment
Some clinicians apply an additional adjustment to the four classic formulas to loosely account for skeletal frame size, since two people of the same height can have very different bone structure:
| Frame Size | Adjustment |
|---|---|
| Small Frame | −10% from base formula result |
| Medium Frame | No adjustment |
| Large Frame | +10% from base formula result |
A simple way to estimate your own frame size is wrist circumference relative to height, though this method is itself only a rough approximation and not a clinically standardized measurement.
Worked Examples
Height over 5 feet = 10 inches. Devine = 50 + (2.3 × 10) = 73.0 kg (161 lb). Hamwi = 48 + (2.7 × 10) = 75.0 kg (165 lb). Healthy BMI range at 178 cm ≈ 58.6 – 78.9 kg (129 – 174 lb).
Height over 5 feet = 4 inches. Devine = 45.5 + (2.3 × 4) = 54.7 kg, then −10% for small frame = 49.2 kg (108 lb). Robinson = 49 + (1.7 × 4) = 55.8 kg, then −10% = 50.2 kg (111 lb).
Height over 5 feet = 14 inches. Miller = 56.2 + (1.41 × 14) = 75.9 kg, then +10% for large frame = 83.5 kg (184 lb). Healthy BMI range at 188 cm ≈ 65.4 – 88.0 kg (144 – 194 lb) - showing the large-frame adjustment pushes toward the top of the healthy BMI band, which is a useful cross-check.
Which Formula Should You Trust?
- For a quick clinical reference point: Devine remains the most commonly cited in medicine, particularly for drug dosing calculations by pharmacists and physicians.
- For a modern, evidence-based health range: the healthy BMI range method is generally preferred by public health bodies today, since it produces a range rather than one rigid number and aligns with the same BMI categories used in broader health screening.
- For a general personal reference: averaging all five methods (as this calculator does) gives a reasonable, balanced starting point without over-relying on any one formula's assumptions.
Why These Formulas Fall Short
Every formula on this page uses only height and sex (with an optional frame-size guess) - none of them measure muscle mass, body fat percentage, age, bone density, or overall fitness. Two people of identical height can have very different healthy weights depending on how much muscle they carry, and these formulas cannot tell the difference. They are decades-old population averages, several originally built for a narrow clinical purpose like drug dosing, not personalized health assessments.
Better Alternatives for Athletes
For muscular individuals, athletes, and bodybuilders, height-based ideal weight formulas are often the least useful tool available, since they systematically underestimate a healthy weight for anyone carrying above-average muscle mass. Body fat percentage (via skinfold calipers, bioelectrical impedance, or DEXA scan) and waist circumference are generally far more meaningful measurements for this population, since they directly assess composition rather than inferring it from height alone.
Common Mistakes
- Treating one formula's result as a hard target. Every formula here is an estimate with several kilograms/pounds of built-in disagreement between methods.
- Ignoring muscle mass entirely. Muscular individuals will consistently show "above ideal" on these formulas despite being at a genuinely healthy body composition.
- Confusing ideal weight with the Devine formula's original medical purpose. It was built for medication dosing precision, not as personal wellness guidance.
- Skipping the frame-size context. Ignoring skeletal frame differences can make the same formula result feel wrong for people with genuinely different bone structures.
- Not cross-checking against the healthy BMI range. The BMI range method gives useful lower and upper bounds that the older single-number formulas don't provide.
Glossary
- Ideal body weight (IBW)
- A height-and-sex-based estimate of a reference body weight, originally developed largely for clinical dosing purposes.
- Devine formula
- The most widely cited IBW formula, published in 1974, originally created to standardize medication dosing.
- Healthy BMI range
- The weight range corresponding to a BMI of 18.5 to 24.9 at a given height; the more current, evidence-based standard.
- Body frame size
- A loose classification (small/medium/large) of skeletal size, sometimes used to adjust IBW formula results by roughly ±10%.
- Body composition
- The proportion of a person's body made up of fat versus lean mass (muscle, bone, water), not captured by height-based formulas.
Frequently Asked Questions
Q: What is the most accurate ideal weight formula?
A: No single ideal weight formula is universally most accurate, since Devine, Robinson, Miller, Hamwi, and the healthy BMI range method were each derived from different study populations and purposes. The Devine formula is the most widely used in clinical medicine, especially for medication dosing, while the healthy BMI range method is generally considered the most evidence-based for assessing general health risk today. Comparing several methods side by side, as this calculator does, gives a more realistic range than trusting any single number.
Q: How is ideal body weight calculated with the Devine formula?
A: The Devine formula, published in 1974, calculates ideal body weight as: for men, 50 kg plus 2.3 kg for each inch over 5 feet in height; for women, 45.5 kg plus 2.3 kg for each inch over 5 feet in height. It was originally developed to help standardize medication dosing calculations, not as a general wellness target, though it has since become one of the most widely cited ideal weight formulas in medicine.
Q: Why do different ideal weight formulas give different results?
A: Each formula (Devine, Robinson, Miller, and Hamwi) was developed independently, decades apart, using different research populations and different original purposes - some for drug dosing, others for general weight assessment. Because of this, they don't perfectly agree, and results for the same person can vary by several kilograms or pounds between formulas, which is why most sources treat ideal weight as a range rather than one exact number.
Q: Does ideal weight account for muscle mass or body frame?
A: The classic Devine, Robinson, Miller, and Hamwi formulas are based only on height and sex, so they do not directly account for muscle mass or body frame size. Some versions add a body frame adjustment - roughly subtracting 10% for a small frame or adding 10% for a large frame - to partially account for skeletal size differences, but none of these formulas measure muscle mass directly the way body composition testing does.
Q: Is ideal body weight the same as a healthy weight?
A: Not exactly. Ideal body weight formulas like Devine were originally created for specific clinical purposes such as medication dosing, while a healthy weight range is more commonly assessed today using BMI (18.5 to 24.9) combined with other measures like waist circumference and body composition. The healthy BMI range method is generally considered a more current, evidence-based way to think about a healthy weight range than the older ideal weight formulas alone.
Q: Should athletes and bodybuilders trust ideal weight calculators?
A: Not without caution. Ideal weight formulas are based only on height and sex, so they can significantly underestimate a healthy weight for very muscular individuals, since muscle is denser and heavier than fat. Athletes and bodybuilders are generally better served by body composition measurements (body fat percentage) than by any height-based ideal weight formula, including the ones used on this page.
This calculator provides estimates for informational and educational purposes only and does not constitute medical advice. It applies five distinct height/sex-based estimation formulas (Devine 1974, Robinson 1983, Miller 1983, Hamwi 1964, and healthy BMI range) plus an optional body frame adjustment, none of which measure muscle mass, body fat, or individual health conditions directly. Consult a physician or registered dietitian for guidance specific to your body composition and health history. Sources: Devine BJ (1974); Robinson JD et al. (1983); Miller DR et al. (1983); Hamwi GJ (1964); World Health Organization and CDC healthy BMI range classification.