BMI for 191 cm and 45 kg
A person 191 cm (6'3") tall weighing 45 kg (99 lbs) has a BMI of 12.3 — classified as Underweight. The healthy weight range for this height is 67.5–90.8 kg.
Your BMI score
Quick health screening — not a diagnosis
Your BMI is well below the healthy range and may indicate serious health risk.
What this means
BMI is a quick screening number based only on height and weight. It doesn't distinguish muscle from fat, and shouldn't replace a clinical assessment.
- 18.5–24.9 generally lowest health risk
- 25–29.9 elevated metabolic risk
- 30+ higher long-term risk
BMI range
WHO adult classification
- YouSevere thinness< 16
- Underweight16 – 18.5
- Normal18.5 – 24.9
- Overweight25 – 29.9
- Obese I30 – 34.9
- Obese II35 – 39.9
- Obese III≥ 40
What does this BMI mean?
Severely underweight · BMI 12.3 · Underweight
A BMI of 12.3 falls well below the standard healthy range and is usually flagged as severely underweight. At 191 cm, body weight under 67.5 kg is generally considered too low for adults.
Being underweight isn't automatically a problem, but it can come with lower iron, B12, or calorie reserves. Worth investigating if weight has dropped without trying.
BMI is a screening tool, not a diagnosis. It doesn't know the difference between fat and muscle, doesn't measure where weight sits on the body, and doesn't account for age, sex, or ethnicity-specific cutoffs.
For someone 191 cm tall, weights between 67.5 kg and 90.8 kg fall in the BMI 18.5–24.9 healthy range — roughly 149–200 lbs.
How far from the healthy range?
Target BMI milestones
Weights that would land at common BMI thresholds for 191 cm.
| Milestone | Target weight | vs current |
|---|---|---|
| BMI 18.5 (lower healthy bound) | 67.5 kg(149 lbs) | Gain ~22.5 kg |
| BMI 20 (low-healthy) | 73.0 kg(161 lbs) | Gain ~28.0 kg |
| BMI 22 (mid-healthy) | 80.3 kg(177 lbs) | Gain ~35.3 kg |
Why BMI isn't the whole story
- Muscle vs fat: BMI treats a kilogram of muscle the same as a kilogram of fat. Strength athletes and very muscular builds can land in the overweight band while having low body fat.
- Body shape matters: Two people at the same BMI can carry weight very differently. Waist circumference and waist-to-height ratio capture risk that BMI misses.
- Age, sex, ethnicity: The 18.5–24.9 window is a single global average. Cutoffs adjusted for ethnicity and age can shift the interpretation, especially at the edges of the band.
- Still useful: BMI remains widely used because it's cheap, fast, and roughly predictive at population scale. Treat it as a self-check signal, not a diagnosis.
Nearby BMI combinations
Related
Common questions
Last updated: 2026