Ideal Weight Calculator
Your ideal weight isn't a single number — compare four trusted formulas and a healthy BMI range at a glance.
Sex
These formulas are calibrated for average adult heights — treat the result as a rough estimate.
Ideal body weight
Estimates based on statistical formulas, not medical advice. Ideal body weight also depends on age, frame size and muscle mass.
Four formulas, one question
"Ideal body weight" (IBW) began as a clinical shortcut. Physicians needed a quick target weight to scale medication doses and to set patient goals, so several researchers published height-based formulas across the twentieth century. This tool runs four of the best known — Devine (1974), Robinson (1983), Miller (1983) and Hamwi (1964) — side by side, because none of them is objectively "correct"; each simply reflects the population its author studied.
Every one of these formulas shares the same shape: a base weight at a height of five feet, plus a fixed amount for each inch above that. They differ only in the base and the per-inch increment, and each uses a different value for men and women. That is why, for the same height, the four results spread across a small band rather than landing on one figure.
The formulas side by side
All four are anchored at 5 ft (152.4 cm). Above that height you add the per-inch amount for every inch; the calculator interpolates for fractional inches, so a metric height converts cleanly.
| Formula | Men (base + per inch) | Women (base + per inch) |
|---|---|---|
| Devine | 50.0 kg + 2.3 kg | 45.5 kg + 2.3 kg |
| Robinson | 52.0 kg + 1.9 kg | 49.0 kg + 1.7 kg |
| Miller | 56.2 kg + 1.41 kg | 53.1 kg + 1.36 kg |
| Hamwi | 48.0 kg + 2.7 kg | 45.5 kg + 2.2 kg |
Worked example 1 — a man at 178 cm
178 cm is about 70.1 inches, or 10.1 inches over 5 ft. Using Devine for a man: 50.0 + (2.3 × 10.1) = 50.0 + 23.2 = 73.2 kg. Robinson gives 52.0 + (1.9 × 10.1) = 71.2 kg, and Hamwi gives 48.0 + (2.7 × 10.1) = 75.3 kg. The three sit within about 4 kg of each other — a realistic target band rather than a single number.
Worked example 2 — a woman at 165 cm
165 cm is about 64.96 inches, roughly 4.96 inches over 5 ft. Devine for a woman: 45.5 + (2.3 × 4.96) = 45.5 + 11.4 = 56.9 kg. Miller gives 53.1 + (1.36 × 4.96) = 59.8 kg. The gap between formulas widens for taller people because the per-inch increments differ.
Why a range, not a point
Alongside the four formulas the calculator shows the healthy-weight range implied by a Body Mass Index of 18.5 to 24.9. For a height h in metres the range is 18.5·h² to 24.9·h². At 165 cm that is 18.5 × 1.65² to 24.9 × 1.65² = 50.4 kg to 67.8 kg. Any single "ideal" figure from the formulas above naturally falls inside this wider healthy band, which is often the more useful reference.
Reading the result sensibly
- The formulas assume an average adult frame. A large-boned or heavily muscled person can be healthy well above their formula weight, since muscle is denser than fat.
- None of the formulas use age, so they are not designed for children or teenagers, whose healthy weight is read from growth charts instead.
- At very short or very tall heights the formulas drift, which is why the tool shows a calibration warning outside typical adult ranges.
Important limits
These numbers are statistical estimates, not a medical assessment. Ideal weight depends on body composition, fat distribution, fitness, and health history that no height-only formula can capture. Use the result as a rough orientation point and consult a qualified healthcare professional before setting a weight goal, especially if you have a medical condition.
Sources & further reading
Frequently asked questions
Devine, Robinson, Miller or Hamwi — which ideal-weight formula should I trust?
None of them is the single "true" answer. All four estimate ideal body weight from height and sex, but they were derived from different populations, so they disagree by a few kilograms — that spread is exactly why this ideal weight calculator shows them side by side. The Devine formula (1974) is the most widely used and was originally built for medication dosing; Robinson and Miller (both 1983) usually give slightly lower figures; Hamwi (1964) is the oldest quick rule of thumb. Read them as a range, not a target to the decimal.
Why show a healthy weight RANGE instead of one ideal number?
Because no single number fits every healthy body. The four formulas give point estimates, but real bodies differ in bone structure and muscle. The healthy weight range here comes from the WHO's healthy BMI band (18.5–24.9) applied to your height, so it answers "how much should I weigh" as a span rather than one figure. Sitting anywhere inside that range is generally considered a healthy weight for your height.
Why do men and women get different ideal weights at the same height?
On average, men carry more muscle and denser bone than women at the same height, so every one of these formulas sets a higher baseline for males. That is why the calculator asks for your sex before computing your ideal body weight. The healthy BMI range, by contrast, is identical for both sexes, because BMI itself does not separate by sex.
Ideal weight vs healthy weight vs BMI — what is the difference?
Ideal (body) weight is a single target figure from a formula like Devine or Hamwi. A healthy weight is a range you can sit anywhere within, taken here from a healthy BMI. BMI is the underlying number (weight ÷ height²) used to define that band. This tool shows all three at once: four ideal-weight figures, the healthy weight range, and — if you add your current weight — where you fall relative to it.
Is my height and weight sent to a server?
No. Every calculation in this ideal weight calculator runs entirely in your browser; your height, sex and weight never leave your device. Your last entry is saved only in your browser's localStorage for convenience on your next visit, and you can clear it anytime.