Advanced Ideal Weight Calculator

Ideal Body Weight (IBW) is a weight range derived from scientific formulas that correlate with lowest health risks and optimal health outcomes. IBW is primarily based on height and gender, with adjustments for body frame size. It's used in clinical settings for drug dosing, nutrition planning, and as a general health target.

Different formulas were developed by different researchers at different times, using different populations. Robinson and Miller (1983) updated earlier formulas with larger datasets. Devine (1974) was developed for drug dosing. Hamwi (1964) was for nutrition. Each has slightly different assumptions—using multiple formulas gives you a more reliable range.

No single formula is universally 'best.' Robinson (1983) is most commonly used by physicians. Miller tends to give slightly higher values. Devine is standard in pharmacology. BMI-based (22 × height²) represents the middle of the healthy BMI range. Using the average of all formulas provides the most balanced estimate.

Frame size accounts for bone structure variations. Small-framed individuals have narrower bones and naturally weigh less; large-framed individuals have heavier bone structure. Adjustment is typically ±10%. You can estimate frame size by wrapping your thumb and middle finger around your wrist—overlapping = small, just touching = medium, gap = large.

Robinson formula (1983): Men: 52 kg + 1.9 kg per inch over 5 feet. Women: 49 kg + 1.7 kg per inch over 5 feet. It's a refinement of the Devine formula based on metropolitan insurance data and is the most commonly cited in medical literature for ideal body weight.

Devine formula (1974): Men: 50 kg + 2.3 kg per inch over 5 feet. Women: 45.5 kg + 2.3 kg per inch over 5 feet. Originally developed to calculate drug dosages, it became widely used for general ideal weight estimation. It tends to give slightly lower values for men compared to Robinson.

No—standard IBW formulas use only height and gender, ignoring body composition. A muscular athlete will have a higher healthy weight than formulas suggest. Similarly, someone with low muscle mass might be unhealthy even at 'ideal' weight. For athletes and bodybuilders, body fat percentage is a better metric than ideal weight.

BMI-based ideal weight uses BMI = 22 (middle of healthy 18.5-24.9 range): Ideal Weight = 22 × height². For 1.75m tall person: 22 × 1.75² = 67.4 kg. This is intuitive since it directly corresponds to optimal BMI. The healthy range (BMI 18.5-24.9) gives the full acceptable weight range.

No—ideal weight is a reference range, not a strict target. Being within ±5 kg of the average is typically healthy. More important factors: body composition, waist circumference, blood pressure, cholesterol, blood sugar, energy levels, and how you feel. A range of 'acceptable' weights exists for everyone.

Safe weight change is 0.5-1 kg (1-2 lbs) per week through ~500 calorie daily deficit (for loss) or surplus (for gain). Faster rates increase muscle loss (when losing) or fat gain (when bulking). If you're 10 kg from ideal, expect 10-20 weeks of gradual progress for sustainable results.

Standard IBW formulas don't include age, but research suggests optimal weight may shift slightly with age. Being slightly heavier in older age (BMI 23-25) may actually correlate with better outcomes—possibly due to reserves during illness. However, this remains debated in research. Focus on health markers over age-specific weights.

Ideal weight is a single target or narrow range from formulas. Healthy weight is a broader range (e.g., BMI 18.5-24.9) where health risks are minimized. You can be healthy at weights above or below 'ideal.' Ideal weight is a useful reference point, but healthy weight is the goal—there's flexibility.

The formulas are the same, but optimal ranges may differ by ethnicity. Asian populations may have higher body fat at lower BMI, so some Asian countries use lower BMI cut-offs (23 instead of 25 for overweight). IBW formulas were developed on Western populations and may need adjustment for other groups.

Being underweight (below ideal) can indicate: insufficient nutrition, malabsorption, hyperthyroidism, or other health issues. Risks include weakened immunity, osteoporosis, fertility problems, and muscle loss. If significantly below ideal, consult a healthcare provider. Aim for gradual weight gain through increased calories and strength training.

Many people are healthy above 'ideal' weight—especially if active and muscular. Key health markers matter more than weight alone: blood pressure, cholesterol, blood sugar, waist circumference, energy, and fitness level. Athletes commonly exceed IBW. If markers are good and you feel well, your weight may be right for you.