BMI for 170 cm & 45 kg
Result: 15.6 · Severe Thinness
Body Mass Index
15.6
Severe Thinness
WHO BMI range for this category: Below 16
What a BMI of 15.6 at 170 cm and 45 kg means
A BMI reading of 15.6 for a person 170 cm tall weighing 45 kg is well under the healthy threshold of 18.5 and indicates severe thinness. Bodies in this range typically lack the reserves needed for routine illness recovery and may show measurable hormonal disruption.
For someone 170 cm tall, the WHO healthy BMI range (18.5 – 24.9) corresponds to a body weight between roughly 53.5 – 72.0 kg (117.9 – 158.6 lbs). BMI is a screening tool, not a body composition measurement, so it does not distinguish muscle from fat. Pair it with waist circumference and body fat percentage for a complete picture.
What you would need to weigh at 170 cm to reach each BMI threshold
| Target BMI | Body weight | Difference vs current |
|---|---|---|
| BMI 18.5 (underweight cutoff) | 53.5 kg (117.9 lbs) | +8.5 kg |
| BMI 22 (middle of healthy range) | 63.6 kg (140.2 lbs) | +18.6 kg |
| BMI 25 (overweight cutoff) | 72.3 kg (159.3 lbs) | +27.3 kg |
| BMI 30 (obesity cutoff) | 86.7 kg (191.1 lbs) | +41.7 kg |
BMI for nearby heights and weights
Reference values at similar measurements. Each link is a pre-calculated page.
Looking for the imperial equivalent? See BMI for 5'6" & 100 lbs →
Frequently asked questions
- Is a BMI of 15.6 healthy for 170 cm?
- A BMI of 15.6 at 170 cm is classified as Severely Underweight. The WHO healthy BMI range is 18.5 – 24.9, which for your height translates to roughly 53.5 – 72.0 kg (117.9 – 158.6 lbs).
- What is the ideal weight for someone 170 cm tall?
- The mid-point of the healthy BMI range (BMI 22) for 170 cm is approximately 63.6 kg (140.2 lbs). The full healthy range spans roughly 53.5 – 72.0 kg. Body composition matters more than the exact number — a muscular person can sit at the top of the range and be perfectly healthy.
- How does BMI relate to body fat percentage at 45 kg?
- BMI does not measure body fat directly. Two people at 170 cm and 45 kg can have very different body compositions. A trained athlete at this weight may have 12 – 15% body fat, while a sedentary adult may have 25 – 30%. Use the Body Fat Calculator for a more precise estimate.
- Is BMI accurate for everyone at 170 cm tall?
- BMI is a population-level screening tool. It systematically over-classifies muscular athletes as overweight and under-classifies older adults with sarcopenic obesity. For an individual assessment at 170 cm, combine BMI with waist circumference (men < 94 cm, women < 80 cm at low risk) and body fat percentage.
- How much weight would I need to lose or gain to reach a healthy BMI at 170 cm?
- If your BMI is below 18.5, gaining weight up to the 53.5 kg (117.9 lbs) threshold puts you in the healthy band. If above 25, losing weight toward 72.0 kg (158.6 lbs) does the same. Aim for 0.25 – 0.5 kg per week for sustainable change.
Calculate with your own values
This page shows pre-calculated results for 170 cm and 45 kg. For any other combination, use the full calculators below.