"Ideal weight" sounds like a precise number – but different formulas give different answers. The Broca formula is over 140 years old and widely disputed today; BMI ignores muscle mass and fat distribution; the WHtR (waist-to-height ratio) is considered a more modern health indicator. Our calculator displays all results side by side for a well-rounded picture.
Step by Step: How to Use the Ideal Weight Calculator
- Enter height: in cm, e.g. 175.
- Enter current weight: in kg.
- Select gender: affects the Broca formula (women: −105 instead of −100).
- Waist circumference (optional, for WHtR): measure with a tape at navel height.
- Compare results: The calculator shows the BMI normal range, Broca value and WHtR assessment.
Practical Examples
Man, 180 cm, 82 kg: Broca ideal = 180 − 100 = 80 kg (±10% = 72–88 kg ✓). BMI = 82/3.24 = 25.3 (just overweight). With a waist of 85 cm: WHtR = 0.47 (< 0.5 = good ✓).
Woman, 165 cm, 62 kg: Broca = 165 − 105 = 60 kg (±10% = 54–66 kg ✓). BMI = 22.8 (normal weight ✓). WHtR with 70 cm waist = 0.42 (excellent ✓).
Muscular athlete, 178 cm, 88 kg: BMI = 27.8 (overweight by the formula). But body fat percentage is 12% – elite athlete! Here BMI fails as a health indicator.
Ideal Weight Formulas at a Glance
- Broca: Men: height (cm) − 100; Women: height (cm) − 105 (±10%)
- BMI normal range: 18.5–24.9 → weight = BMI × height²
- WHtR target: waist circumference / height < 0.5
Frequently Asked Questions (FAQ)
- Which ideal weight formula is best?
- No formula is perfect. The WHtR (waist/height < 0.5) is currently considered the most reliable indicator of metabolic health risk. BMI underestimates muscle mass; Broca is outdated. The best method is a medical body composition analysis.
- What does the BMI normal range 18.5–24.9 mean?
- BMI = body weight (kg) / height² (m²). Below 18.5 = underweight; 18.5–24.9 = normal weight; 25–29.9 = overweight; 30 and above = obese. These thresholds apply to adults; separate charts are needed for children and athletes.
- At what waist circumference does health risk increase?
- Elevated risk: men from 94 cm, women from 80 cm waist circumference. Significantly elevated risk: men from 102 cm, women from 88 cm. (WHO recommendations 2023)
