Ideal Weight Calculator

How to use the ideal weight calculator

Before anything else, read this as a rough reference and nothing more. The four formulas behind this tool are dated clinical heuristics from the 1960s through the 1980s, and every one of them was built from just two inputs: height and sex. They know nothing about muscle, frame size, body composition, age, or ethnicity. A muscular athlete, a large-framed person, or anyone whose body simply does not match a half-century-old average can be perfectly healthy well above the number these formulas produce. The range below is a reference point, not a goal to chase and not a verdict on anybody’s body.

To use it, choose a sex and enter a height — the default is 175 cm, and you can switch between centimetres and inches with the toggle. That is all the formulas take, because that is all they were ever given. From those two values the tool runs four separate clinical equations and shows you what each one returns, in both kilograms and pounds.

Read the result as a range — the lowest and the highest of the four formulas, with the other two sitting in between — and not as a single target. We show the spread on purpose. For a 175 cm man the four equations land at roughly 68.7 to 72.0 kg (about 151 to 159 lb); for a 165 cm woman, roughly 56.4 to 59.8 kg. Those gaps of several kilograms are the whole point: four respected formulas, fed identical inputs, disagree by a noticeable margin, which is exactly why a single “ideal weight” is misleading.

The four are named for the researchers who published them — Devine, Robinson, Miller, and Hamwi. They were originally designed to help clinicians scale medication doses to body size, not to tell anyone what they ought to weigh. Because each used a slightly different baseline and slope, they return slightly different numbers from the same height, and none has a stronger claim to being “right” than the others. Showing all four as a band is more honest than picking one and presenting it as the answer.

If you want to understand your own health, these formulas are not the place to look — a healthcare provider is, along with measures the equations ignore entirely, like body composition, fitness, and how you actually feel. The page also carries a short medical-disclaimer line for that reason. Treat the range here as a bit of historical context on how clinicians once estimated body size from height alone, and let the conversation about your own body happen with a professional who can see the whole picture.

The formula

All four formulas work the same way: they start from a base weight for someone exactly 5 feet (60 inches) tall, then add a fixed amount for every inch above that. So a height in centimetres is first converted to inches, and the inches over 5 feet drive the rest. A 175 cm person is 68.9 inches tall, which is 8.9 inches over 5 feet:

Devine (male):   50 + 2.3 × (inches over 5 ft)
Robinson (male): 52 + 1.9 × (inches over 5 ft)
Miller (male):   56.2 + 1.41 × (inches over 5 ft)
Hamwi (male):    48 + 2.7 × (inches over 5 ft)
Devine (female):   45.5 + 2.3 × (inches over 5 ft)
Robinson (female): 49 + 1.7 × (inches over 5 ft)
Miller (female):   53.1 + 1.36 × (inches over 5 ft)
Hamwi (female):    45.5 + 2.2 × (inches over 5 ft)

Worked example with the default — a 175 cm man, which is 68.9 inches, or 8.9 inches over 5 feet. Devine: 50 + 2.3 × 8.9 ≈ 70.5 kg. Robinson: 52 + 1.9 × 8.9 ≈ 68.9 kg. Miller: 56.2 + 1.41 × 8.9 ≈ 68.7 kg. Hamwi: 48 + 2.7 × 8.9 ≈ 72.0 kg. Together those four span roughly 68.7 to 72.0 kg, or about 151 to 159 lb — a range, with no single value inside it carrying more authority than the rest.

Keep in mind what those numbers are and are not. These are dated, height-only formulas: they take sex and height and nothing else, so they cannot account for muscle, frame size, body composition, age, or ethnicity. The output is a rough reference range, not a personal target and not a measure of health. Two people of identical height and sex can both be healthy at weights well apart, and well outside this band — which is why the right place to interpret any of this is a conversation with a healthcare provider, not a formula from decades ago.

Frequently asked questions

Related tools