Ideal Weight Calculator

How Ideal Weight Calculator Works

This calculator estimates a healthy "ideal weight" for your height and sex using four well-known medical formulas -- Devine, Robinson, Miller, and Hamwi -- originally developed for drug-dosing and clinical reference, then averages them into a single number, alongside a separate BMI-based healthy weight range.

Formula & Method

All four formulas share the same shape: a base weight (in kg) for 5 feet (60 inches) of height, plus a fixed amount per inch over that. This calculator first converts your height to inches over 60 (inches − 60), then applies: Devine = 50 + 2.3 × over60 (men) or 45.5 + 2.3 × over60 (women); Robinson = 52 + 1.9 × over60 (men) or 49 + 1.7 × over60 (women); Miller = 56.2 + 1.41 × over60 (men) or 53.1 + 1.36 × over60 (women); Hamwi = 48 + 2.7 × over60 (men) or 45.5 + 2.2 × over60 (women). The displayed result is the simple average of all four. The separate healthy BMI range is calculated from the standard BMI cutoffs of 18.5 and 24.9.

Worked Example

For a man 170 cm tall: that's 66.93 inches, or 6.93 inches over 60. Devine gives 50 + 2.3 × 6.93 ≈ 65.9 kg, Robinson gives ≈ 65.2 kg, Miller gives ≈ 66.0 kg, and Hamwi gives ≈ 66.7 kg -- averaging to about 65.9 kg. The separate healthy BMI-based range for the same height is about 53.5 kg to 72.0 kg.

Frequently Asked Questions

Why do the four formulas give slightly different results?

Devine, Robinson, Miller, and Hamwi were each developed independently, using different reference populations and study designs, mostly for clinical purposes like drug dosing rather than general fitness advice -- so a small spread between them is expected and normal.

Why is there a separate "Healthy BMI Range" figure?

The four named formulas estimate a single "ideal" number based on height and sex alone, while the BMI range shows the full span of weights considered "normal" BMI (18.5 to 24.9) for that height -- a wider, more forgiving band that many people fall within even if it differs from the four-formula average.

Is "ideal weight" the same as a healthy weight for everyone?

Not necessarily. These formulas only use height and sex, so they don't account for muscle mass, frame size, age, or overall health -- someone quite muscular or with a larger frame may sit above these numbers while still being perfectly healthy.