Ideal Weight Calculator
This free ideal weight calculator estimates a target body weight from your height and gender, using the Devine and Robinson formulas. Nothing you enter is sent anywhere or stored.
How to Use It
- Select your gender.
- Enter your height.
- Your estimated ideal weight, from both the Devine and Robinson formulas, updates instantly.
How It Works
Both formulas start from a base weight for a 5 foot tall person, then add a fixed amount for every inch of height beyond that, with a different base weight and per-inch amount for each gender. The headline estimated ideal weight shown here is the average of the two formulas, a common way to get a single, more robust number rather than treating either formula as uniquely correct.
Formulas
Devine: men = 50 kg + 2.3 kg × (height in inches − 60); women = 45.5 kg + 2.3 kg × (height in inches − 60)
Robinson: men = 52 kg + 1.9 kg × (height in inches − 60); women = 49 kg + 1.7 kg × (height in inches − 60)
A worked example: a man who is 5'10" (70 inches) tall gives a Devine estimate of 73.0 kg (160.9 lb) and a Robinson estimate of 71.0 kg (156.5 lb), averaging to an estimated ideal weight of 72.0 kg (158.7 lb). A woman who is 5'5" (65 inches) tall gives a Devine estimate of 57.0 kg (125.7 lb) and a Robinson estimate of 57.5 kg (126.8 lb), averaging to 57.3 kg (126.2 lb).
This is a general population estimate from formulas originally developed for medical drug dosing calculations, not a personalized health recommendation or fitness target. Everything runs client-side in your browser. Nothing you enter is sent anywhere or stored.
Frequently Asked Questions
Why does this show two different formulas instead of one number?
The Devine and Robinson formulas are both well established, and they can disagree by a few pounds, without either one being universally regarded as more accurate. Showing both, along with their average as the headline estimate, gives a more honest picture than presenting a single formula as a definitive answer.
Why do these formulas only apply from 5 feet tall and up?
Both formulas are defined relative to a 5 foot (60 inch) baseline and were never derived for shorter statures. Below that height, the math would need to extrapolate outside the range these formulas were built for, so this calculator states that limitation plainly with a clear error rather than returning an unreliable number.
How is this different from the BMI Calculator?
BMI Calculator returns a weight category (underweight, normal, overweight, obese) covering a whole range of weights for your height. This tool instead returns a single target weight number from published formulas. The two are related but answer different questions: which range am I in, versus what is one reasonable target weight for my height.
Where do these formulas actually come from?
Both were originally developed for medical purposes, specifically calculating drug dosages that need to scale with a patient's body weight, not as a fitness or aesthetic goal. Devine dates to 1974 and Robinson is a 1983 refinement of it. They became widely cited "ideal weight" estimates well outside their original clinical context, which is worth knowing when deciding how much weight to put on the result.
Does this account for muscle mass or body frame size?
No, like BMI, these formulas take only height and gender as inputs, not muscle mass, bone structure, or frame size. Two people of the same height and gender but very different builds get the identical estimate here, even though a healthy weight for each of them may genuinely differ.