Ideal Body Weight Calculator
Calculate your ideal body weight using multiple clinical formulas. Results are estimates — see the About section for important context on IBW limitations.
Adjusts result by ±5% for bone frame size
Formula Comparison
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About Ideal Body Weight — Limitations and Context
The concept of "ideal body weight" originated in the insurance industry in the 1940s and 50s, when actuaries noticed correlations between weight and mortality. The clinical formulas used here — Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964) — were primarily designed for calculating medication doses in hospitalised patients, not as fitness targets for healthy adults.
These formulas share a fundamental limitation: they use only height and sex as inputs. They completely ignore body composition. A 180 cm male who weighs 85 kg of mostly lean muscle will have the same calculated IBW as a sedentary 180 cm male carrying significant body fat, even though their health profiles are dramatically different.
For strength athletes, bodybuilders, and regular gym-goers, IBW estimates are often unrealistically low. It is common for competitive powerlifters and weightlifters to be 15–30 kg above their calculated IBW while having excellent metabolic health markers. If you train regularly, body fat percentage is a far more meaningful metric than scale weight relative to any formula.
Use these numbers as a rough orientation, not a goal. If your weight is well within range, great. If it is significantly outside range, that is a prompt to speak to a healthcare provider — not a reason to crash-diet to hit a formula target.
Frequently Asked Questions
What is ideal body weight (IBW)?
Ideal body weight is an estimated target weight associated with good health outcomes for a given height and sex. It was originally developed in the 1970s by Dr. B.J. Devine for clinical drug dosing — not as a fitness goal. The Devine formula remains the most widely cited, though several alternatives exist.
Which IBW formula is most accurate?
No single formula is universally accurate. The Devine formula is the most commonly used in clinical settings. The Robinson and Miller formulas produce slightly different values. The Hamwi formula, developed for diabetic patients, tends to give slightly higher results. For most people the formulas agree within a few kilograms.
Is IBW relevant for athletes and muscular people?
IBW is a poor target for athletes or anyone with above-average muscle mass. A 180 cm male powerlifter who weighs 95 kg of mostly lean mass will be told their IBW is around 75 kg — a number that would require losing significant muscle. For athletes, a better approach is to track body fat percentage or performance metrics rather than a fixed weight target.
What does the frame size adjustment mean?
The ±5% frame size adjustment is a simple correction for people with naturally smaller or larger skeletal frames. A small-framed person carries less bone mass, so a slightly lower IBW estimate may be appropriate. A large-framed person can healthily carry a few extra kilograms. It is a rough heuristic — wrist circumference relative to height is one clinical method for estimating frame size.
Should I use IBW as my weight loss goal?
IBW can serve as a rough orientation, but it should not be treated as a precise target. Many people are healthy at weights above or below their calculated IBW. A better approach is to aim for a body fat percentage in a healthy range (roughly 10–20% for men, 18–28% for women) and monitor health markers like blood pressure, blood glucose, and energy levels rather than chasing a single number.