Ideal Weight Calculator
Estimate ideal body weight from height and sex using the Devine, Robinson, Miller and Hamwi formulas, plus the healthy BMI 18.5–24.9 weight range.
Frame is traditionally judged by wrist size against height. It moves the four formulas, not the healthy-BMI range; if unsure, leave it at medium.
Which frame? Wrist size for your height
| Height | Small (−10%) | Medium (as published) | Large (+10%) |
|---|---|---|---|
| over 5 ft 5 in (165 cm) | under 6.5 in (16.5 cm) | 6.5 in (16.5 cm) – 7.5 in (19.1 cm) | over 7.5 in (19.1 cm) |
Wrist circumference, measured just above the wrist bone. The row for the height above is marked. Source: MedlinePlus Medical Encyclopedia, “Body frame size”.
- Devine (1974) — devised for drug dosing, and still the one clinics quote most
- Robinson (1983) — Devine re-fitted on a larger sample; always between Devine and Miller
- Miller (1983) — starts highest at 5 ft and rises most slowly with height
- Hamwi (1964) — the oldest of the four, a bedside rule of thumb
Healthy BMI range: 56.7 kg – 76.3 kg
The equations
- Devine: 50 kg + 2.3 kg × (height in inches − 60)
- Robinson: 52 kg + 1.9 kg × (height in inches − 60)
- Miller: 56.2 kg + 1.41 kg × (height in inches − 60)
- Hamwi: 48 kg + 2.7 kg × (height in inches − 60)
A small frame takes 10% off each result and a large one adds 10%.
| Class | BMI | Weight |
|---|---|---|
| Severe thinness | under 16 | under 49 kg |
| Moderate thinness | 16 – 17 | 49 kg – 52.1 kg |
| Mild thinness | 17 – 18.5 | 52.1 kg – 56.7 kg |
| Normal | 18.5 – 25 | 56.7 kg – 76.6 kg |
| Overweight | 25 – 30 | 76.6 kg – 91.9 kg |
| Obese (class I) | 30 – 35 | 91.9 kg – 107.2 kg |
| Obese (class II) | 35 – 40 | 107.2 kg – 122.5 kg |
| Obese (class III) | 40 and up | 122.5 kg and up |
Each row runs up to, but not including, where the next one starts.
🔒 Calculated in your browser. Four classic clinical formulas plus the healthy-BMI weight range — estimates for a frame, not a target; healthy weight is a range, not one number.
Four formulas plus a BMI range
Enter your height and sex to see ideal-body-weight estimates from the Devine, Robinson, Miller and Hamwi formulas — the classic equations used in clinical dosing and fitness. Alongside them, the tool shows the healthy weight range for your height at BMI 18.5–24.9.
A range, not a target
These formulas were built for medication dosing and give a single figure per height, but real healthy weight is a range that depends on build, muscle and body composition. Treat the numbers as a rough reference, not a goal. Everything is calculated in your browser.
These four formulas were not written for you
Devine, Robinson, Miller and Hamwi all come from clinical practice, and Devine's — the oldest and still the most cited — was published in 1974 to size drug doses, not to tell anyone what to weigh. Each is the same shape: a base weight at five feet, plus a fixed amount for every inch above that. They contain no term for your muscle, your age or your health, and none for your build — the frame option on this page is a common rule of thumb applied on top of them, not part of any formula. Without it, two people of the same height get the same answer whatever else is true of them. To judge your frame, “Which frame? Wrist size for your height” gives the MedlinePlus wrist-circumference bands in inches and centimetres, with the row for your height marked.
The BMI range is what clinicians use
Alongside the four is the weight range that puts you between BMI 18.5 and 24.9 at your height — a band rather than a point, and the one clinicians actually use when they mean healthy weight. From five feet up, the four formulas land in its lower half for a woman and in its upper half for a man. Below five feet the formulas are not extended downwards, because a straight line continued past the data it was fitted to starts returning weights that no source supports; the page shows the base weight and says so.
Frequently asked questions
What is ideal body weight?
A formula-based estimate of a "reference" weight for a given height and sex, originally for medication dosing. It ignores build and muscle, so use the BMI range too.
Which of the four numbers should I use?
None of them, as a target. They exist so that two clinicians sizing the same dose get the same answer. If you want a figure to aim at, the BMI range is the defensible one, and it is a range on purpose.
Why is my height under five feet treated differently?
All four formulas are defined as a base weight plus so much per inch over five feet. Below that there is no agreed way to continue them, so the page returns the base weight and marks it rather than inventing a downward slope.
Does it account for muscle?
No, and neither does BMI. A heavily muscled person will read as overweight on both. That is a known limit of every height-only measure, not a fault in the arithmetic.
Can I enter feet and inches, or account for my frame?
Yes. Height can be typed as feet and inches as a pair, and a frame option moves the formulas' results down for a small frame and up for a large one — a common rule of thumb on top of the formulas, not part of them.
Is there one number to quote, and can I see the equations or the weight for each BMI class?
Yes. A fifth tile, “Average of the four”, averages the formulas' results, and the copied line opens with it. “The equations” writes each formula out for the sex chosen, with the same coefficients the arithmetic uses and a line for the frame adjustment. And “Weight for every BMI class at this height” lists every WHO class, not only the healthy band, with the BMI range and the weight range each spans at your height.
How do I know whether my frame is small, medium or large?
Open “Which frame? Wrist size for your height” under the frame option: it gives the MedlinePlus wrist-circumference bands for women and for men, in inches with centimetres beside them, and marks the row for the height you typed. Measure the wrist just above the wrist bone. The source gives no row for shorter men, and the page says so — leave the frame at medium then.