☾ Ideal Weight Calculator
Compare your ideal weight across 4 scientific formulas: Devine, Robinson, Miller, and Hamwi.
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Start Free AI Coaching ✦🧬 Understanding Ideal Weight Formulas
Ideal body weight formulas were developed for clinical dosing and health screening. They estimate a healthy weight based on height and gender. No single formula is perfect — that's why we show four and highlight the range.
✦ Which formula is the most accurate? ↓
No single formula is universally most accurate. The Devine formula is the most widely used in clinical settings, but Robinson and Miller formulas tend to give more realistic estimates for shorter and taller individuals. Viewing the range from all four gives you the best picture.
✦ How does frame size affect ideal weight? ↓
People with larger bone structures naturally carry more weight. A simple way to estimate frame size: wrap your thumb and middle finger around your wrist. If they overlap, you have a small frame; if they just touch, medium; if there's a gap, large. The calculator adjusts by ±10% for small/large frames.
✦ Why does my weight fluctuate during my menstrual cycle? ↓
Hormonal changes — especially rising progesterone in the luteal phase — cause water retention that can add 1–3 kg (2–6 lbs) to your scale weight. This is completely normal and doesn't reflect actual fat gain. For the most consistent readings, weigh yourself at the same time during the follicular phase.
✦ Why do the four formulas give different results? ↓
Each formula was developed from different population data and time periods. The Devine formula (1974) is the most widely used in clinical pharmacology. Robinson (1983) and Miller (1983) revised Devine's numbers to better fit real-world observations. Hamwi (1964) is the oldest and tends to be the most generous. Viewing all four gives you a realistic spread.
✦ Should I aim for the lowest number in the range? ↓
No. The lowest number assumes a very small frame and minimal muscle mass. For most women who exercise regularly, the middle or upper portion of the range reflects a healthier, more sustainable target. Chasing the bottom of the range often leads to muscle loss and hormonal issues — especially amenorrhea if you dip below your body's fat threshold.
✦ How does muscle mass affect my ideal weight? ↓
Muscle tissue is denser than fat, so a woman with more lean mass will weigh more at the same clothing size. Ideal weight formulas don't account for body composition — a 65kg woman at 22% body fat looks and feels very different from a 65kg woman at 32% body fat. If you strength train regularly, focus on body fat percentage and how your clothes fit rather than scale weight alone.
📖 Getting Started
Enter your gender, height, and frame size. The calculator runs four clinical formulas — Devine, Robinson, Miller, and Hamwi — simultaneously and displays the full range. Frame size adjusts the final range by ±10% for small or large frames.
To determine your frame size, wrap your thumb and index finger around your wrist. If they overlap, you have a small frame; if they just touch, medium; if there's a gap, large. This simple test correlates with wrist circumference-based clinical methods.
📊 Interpreting Your Ideal Weight Range
The range from all four formulas gives you a realistic band rather than a single number. Most women find their comfortable, sustainable weight falls within this band when eating intuitively and training consistently — not at the bottom of the range through restriction.
These formulas were originally designed for clinical use (drug dosing, health screening) — not as aesthetic ideals. They don't account for muscle mass, body fat distribution, or individual metabolic differences. Use the range as a general reference point, not as a target to chase.
⚕️ Medical Perspective on Ideal Weight
If your current weight is significantly above or below the calculated range and you experience health symptoms — missed periods, chronic joint pain, persistent fatigue, or metabolic markers outside normal ranges — discuss a weight management plan with your physician. Drastic weight loss attempts (crash diets, extreme deficits) are clinically discouraged because they trigger muscle loss, hormonal disruption, and metabolic slowdown.