Examples
BMI Comparison Calculator — Worked Examples
2 real worked examples for the BMI Comparison Calculator calculator. See how we solve common scenarios with full step-by-step math.
1
Athlete with high BMI but low body fat
Scenario
A 28-year-old male bodybuilder, 180 cm, 92 kg, waist 82 cm, neck 40 cm.
Inputs
- Height
- 180 cm
- Weight
- 92 kg
- Waist
- 82 cm
- Neck
- 40 cm
Calculation steps
- BMI = 92 / (1.80)² = 28.4
BMI says overweight.
- US Navy BF% = 86.010 × log10(82 − 40) − 70.041 × log10(180) + 36.76
- BF% ≈ 11.2%
- Comparison: BMI 28.4 (overweight) vs BF% 11.2 (athletic)
Result
BMI is misleading here. Body fat % reveals athlete-level composition. Use BF% to clarify.
2
Sedentary adult with normal BMI but high body fat
Scenario
A 55-year-old woman, 165 cm, 62 kg, waist 90 cm, neck 32 cm, hip 100 cm.
Inputs
- Height
- 165 cm
- Weight
- 62 kg
- Waist
- 90 cm
- Neck
- 32 cm
- Hip
- 100 cm
Calculation steps
- BMI = 62 / (1.65)² = 22.8
BMI says normal.
- Women's US Navy BF% = 163.205 × log10(90 + 100 − 32) − 97.684 × log10(165) − 78.387
- BF% ≈ 35%
- Comparison: BMI 22.8 (normal) vs BF% 35% (high)
Result
BMI misses the "skinny fat" pattern. Waist-to-hip ratio = 0.90 (high risk).