Ideal Weight Calculator
Free ideal weight calculator. Compute ideal body weight using the Devine, Hamwi, Robinson, and Miller formulas from height — with healthy BMI range comparison.
Quick answer
Devine formula (men): 50 kg + 2.3 kg per inch over 5 feet. Women: 45.5 kg + 2.3 kg per inch over 5 feet. The calculator also shows Hamwi, Robinson, and Miller variants. All four give similar numbers within 5-10 lbs and are starting points, not absolute targets.
Ideal Weight Calculator
Ideal weight estimates (lbs)
How it works
Shows results from four classic IBW formulas (Devine, Hamwi, Robinson, Miller), each developed for clinical drug-dosage calculations. Also displays the BMI-based "healthy weight" range (BMI 18.5-24.9), which is what most modern doctors actually use.
When to use it
Setting a weight loss or gain target, comparing across formulas, or sanity-checking a specific number a coach gave you. The four formulas typically agree within 5-10 lbs.
Common mistakes
Treating "ideal weight" as a single magic number. These formulas don't account for muscle mass, frame size, or body composition — a heavily-muscled athlete will be "overweight" by every IBW formula and BMI alike. Use ideal weight as a directional guide, not a hard target.
How the ideal weight calculator works
Four formulas dominate clinical practice: Devine (1974, used for medication dosing), Hamwi (1964, used in nutrition), Robinson (1983, slight variation on Devine), and Miller (1983, modified for greater accuracy in shorter people). All start with a baseline weight at 5 feet of height and add a fixed amount per inch above. The calculator runs all four and displays them side-by-side. The 'right' weight for an individual usually falls within the ranges all four produce.
When to use it
Setting a long-term weight loss target informed by clinical formulas rather than diet-industry promises. Calibrating expectations during a cut — the formulas give a defensible 'goal weight' that doesn't vanity-undercut. Discussing weight goals with a healthcare provider using the same vocabulary they use. Comparing to BMI's healthy range (typically a 30-40 lb spread for any given height).
Common mistakes
- Using ideal weight as a strict target. The formulas were developed for medication dosing, not optimal aesthetics or athletic performance. Healthy adults can be 10-20% above 'ideal' and have excellent health markers.
- Ignoring frame size. The original formulas assumed medium frames. Large-framed people are typically 5-10 lbs above ideal at the same height; small-framed people 5-10 lbs below.
- Confusing ideal weight with BMI. Ideal weight is a single number; healthy BMI is a range. The two won't always agree exactly, especially for very short or very tall individuals.
Frequently asked questions
What's my ideal body weight?
Use the calculator above with your height and sex. Ideal weight per Devine: men 50 kg + 2.3 kg per inch over 5 feet; women 45.5 kg + 2.3 kg per inch over 5 feet. Other formulas (Hamwi, Robinson, Miller) give similar numbers.
Are ideal weight formulas accurate?
They're starting points, not strict targets. The formulas were developed for medical drug dosing. Healthy adults can be 10-20% above the calculated ideal with excellent health. Body fat % and waist circumference are more meaningful health indicators.
Should I aim for ideal weight or healthy BMI?
Healthy BMI (18.5-24.9) is a range that lines up with ideal weight formulas roughly. For most people, the lower half of the healthy BMI range matches the formulas. Use either as a starting frame, refine with body composition and how you actually feel.