Ideal Weight Calculator
Find your ideal body weight using five established medical formulas
Frame size adjusts Hamwi formula by ±10%. Determine by wrapping your thumb and index finger around your wrist: overlap = small, touch = medium, gap = large.
Results & Details
// Your Weight vs Healthy Range
// Progress Toward Ideal Weight
// All 5 Formulas
// BMI Healthy Weight Range (18.5–24.9)
What Is Ideal Body Weight?
Ideal Body Weight (IBW) formulas were originally developed in clinical settings to estimate appropriate medication dosages and anaesthetic amounts. Over time they became widely used as reference points for healthy weight ranges, though none of them account for muscle mass, bone density, or individual variation.
The Five Formulas
Which Formula Should I Use?
There is no universally "correct" formula — they were each developed for different purposes. The Devine formula is the most widely cited and used. The average of all five formulas (shown as your result) gives a reasonable central estimate. The BMI healthy range (18.5–24.9) is the most commonly used modern reference.
Limitations
These formulas were developed on limited populations and do not account for muscle mass, age-related body composition changes, ethnicity, or individual variation. A bodybuilder may have an "above ideal" weight while being very lean. A sedentary person may be within range while carrying excess fat. Use these figures as a general guide, not a target to obsess over.
"Ideal Weight": Where the Formulas Come From and What They're Worth
Built and verified by Andrius R. · Updated June 2026
Every ideal weight formula gives a confident, precise answer — which hides an awkward truth about where these equations came from and what they can't see. Use them as a rough compass, not a verdict.
The same person through four formulas
| Formula | Structure | Result |
|---|---|---|
| Devine (1974) | 50 kg + 2.3 kg per inch over 5 ft | ~70.5 kg |
| Robinson (1983) | 52 kg + 1.9 kg/inch | ~68.9 kg |
| Miller (1983) | 56.2 kg + 1.41 kg/inch | ~68.7 kg |
| Hamwi (1964) | 48 kg + 2.7 kg/inch | ~72.0 kg |
A ~3 kg spread for the same height — and here's the part most calculators skip: the Devine formula was created to estimate drug doses, not to define healthy weight. Hamwi's was a quick clinical rule of thumb from a diabetes handbook. These equations were never validated as health targets; they survive because they're simple.
The more defensible alternative: a healthy range
The healthy-BMI approach inverts BMI: weight = BMI × height². For 175 cm, the 18.5–24.9 healthy band spans ~56.7 to 76.3 kg — a 20 kg range, not a single number. That width isn't vagueness; it's honesty. Bodies with more muscle, denser bones, or broader frames legitimately sit higher in (or above) the range while being perfectly healthy. Any formula that outputs one number to the decimal point is manufacturing precision the underlying science doesn't have.
What "ideal" can't see
- Composition: at 175 cm and 76 kg you can be a soft 28% body fat or a muscular 15% — same "ideal weight" verdict, very different realities. The body fat calculator answers what these formulas can't.
- Fat location: health risk tracks waistlines better than scale weight; keeping your waist under half your height is a stronger single check than hitting Devine's number.
- Frame and proportions: the formulas assume average builds. Long legs, broad shoulders, or a stocky frame all shift the sensible target.
- Trajectory: a stable weight with good habits beats yo-yoing toward a formula's target. Direction and behavior predict health outcomes better than distance from an arbitrary number.
How to actually use this calculator
Treat the formula outputs as a sanity band: if all four cluster 15 kg below your current weight, that's information worth acting on — gradually, via a moderate deficit sized with the calorie calculator. If you're within or near the healthy BMI range, shift attention from the scale to composition, waist, fitness, bloodwork, and how you feel. There is no prize for weighing exactly what a 1974 dosing equation suggests.
// Not a Magic Number
Ideal weight formulas were designed for medication dosing, not as strict health targets. A range is always more meaningful than a single number.
// BMI Range Preferred
The WHO BMI healthy range (18.5–24.9) is the most widely used modern reference. It gives a weight range rather than a single target.
// Muscle vs Fat
A muscular person may be "above ideal" weight while being very healthy. These formulas cannot distinguish muscle from fat.
// Focus on Health
Energy levels, sleep quality, blood pressure and fitness are better health indicators than hitting an exact weight target.