Ideal Weight Calculator
Calculate your ideal body weight using three evidence-based formulas. Results shown in both kg and lbs.
Ideal Body Weight
Devine · Robinson · Miller formulas
Ideal Body Weight (IBW) formulas were originally developed for medication dosing in clinical settings, not as fitness targets. They provide a rough reference range — not a personal goal. Athletes and muscular individuals will often weigh more than IBW while remaining healthy.
IBW Formula Comparison
| Formula | Male (per inch over 5ft) | Female (per inch over 5ft) |
|---|---|---|
| Devine (1974) | 50 kg + 2.3 kg | 45.5 kg + 2.3 kg |
| Robinson (1983) | 52 kg + 1.9 kg | 49 kg + 1.7 kg |
| Miller (1983) | 56.2 kg + 1.41 kg | 53.1 kg + 1.36 kg |
What Is Ideal Body Weight and How Is It Calculated?
Ideal body weight (IBW) formulas estimate an appropriate body weight based primarily on height and sex. They were originally developed for clinical dosing calculations — certain medications are dosed based on IBW rather than total body weight to avoid toxicity in obese patients. Over time, they've been adopted by fitness and nutrition professionals as a starting reference for weight goal-setting. The most widely used formulas are Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964) — each yielding slightly different estimates from the same inputs.
It is critical to understand that IBW formulas were derived primarily from actuarial data from insurance company mortality tables, not from athletic or body composition research. They do not account for muscle mass, frame size, or body fat percentage. A competitive powerlifter at 90 kg with 12% body fat may have an IBW of 75 kg according to the Devine formula — yet this athlete is in peak health. IBW is best interpreted as a rough reference range, not a target, and should always be contextualized with body fat percentage data.
For fitness purposes, a more meaningful target combines IBW with a goal body fat percentage. For example: if your IBW is 75 kg and your goal is 15% body fat, your lean mass target would be 75 × 0.85 = 63.75 kg lean mass at target weight. This approach, combined with tracking body fat percentage over time rather than scale weight alone, gives a far more useful framework for physique progression than any IBW formula can provide on its own. Use this as a starting point and calibrate against your actual body composition data.