Free online tool
Ideal Weight Calculator
Four classic formulas, all shown side by side, based on your height and gender.
| Formula | Ideal weight |
|---|---|
| Devine | 70.5 kg (155.3 lb) |
| Robinson | 68.9 kg (151.9 lb) |
| Miller | 68.7 kg (151.6 lb) |
| Hamwi | 72.0 kg (158.8 lb) |
Where "ideal weight" comes from
The concept dates back to insurance actuarial tables from the mid-20th century, when statisticians tried to correlate weight with mortality risk. Several doctors — Devine, Robinson, Miller, and Hamwi — each proposed slightly different formulas, all based on height and gender. None is universally accepted as "the" answer, which is why this tool shows all four.
How to interpret the numbers
Treat the range as a rough guide, not a target. Frame size, muscle mass, ethnicity, and age all shift what's actually healthy for you. If you want a more individualized number, combine this with a BMI check and a body-fat estimate rather than relying on any single figure.
+Which formula is most accurate?
There's no clear winner. Devine is the most widely used in medical settings, especially for drug dosing.
+Does it work for children?
No. Pediatric weight guidelines use growth curves specific to age and are very different from adult formulas.
What 'ideal weight' formulas actually estimate
Several decades-old formulas — Devine, Robinson, Miller, and Hamwi among them — estimate a reference body weight from height and gender alone, originally created by clinicians to help calculate medication dosages rather than to define an aesthetic target.
These formulas predate modern body composition tools and were never meant to describe an individual's optimal appearance or fitness level; they were a practical shortcut for pharmacists and doctors who needed a quick weight estimate when a patient couldn't be weighed immediately.
How the formulas differ
The Devine formula, still common in clinical settings, starts from a base weight for 152 cm of height and adds a fixed amount per centimetre above that, with different constants for men and women. Because each formula was built from different reference populations, they can disagree by several kilograms for the same height, which is a useful reminder that none of them is a single objective truth.
Worked example
For a man who is 175 cm tall, the Devine formula gives 50 kg plus 2.3 kg for each inch over 5 feet. At 175 cm, that's roughly 9.8 inches over 5 feet, so the estimate comes to about 72.5 kg. A different formula might place the same height's ideal weight anywhere from 68 to 75 kg.
Run the same height through the Robinson formula instead, which uses a slightly lower base weight and a smaller per-inch increment, and the estimate shifts down a couple of kilograms — illustrating why quoting one formula as definitive is misleading without mentioning which one was used.
Why these formulas were never about fitness
Because Devine and similar equations were built to estimate lean body mass for drug dosing, they don't account for athletic build, bone structure, or the healthy weight gain from strength training — a bodybuilder or powerlifter can weigh 20 kg or more above these formulas' output while carrying very little excess fat, which is one reason these numbers are gradually being replaced in clinical practice by body composition and waist circumference measures.
Treat the range, not the number, as useful
Frame, muscle mass, and bone density all shift what a healthy weight looks like for a given height, so this output is best used as a rough reference point for conversation with a healthcare provider rather than a strict goal to chase — it isn't a personalised medical recommendation and shouldn't be treated as one.
Modern alternatives clinicians increasingly prefer
Many practitioners now lean on waist-to-height ratio or direct body composition measurement instead of decades-old height-weight formulas, since these better reflect metabolic risk regardless of frame size. Ideal weight formulas persist mainly because they're fast and require no equipment, not because they've been shown to outperform newer approaches for assessing individual health.
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