BMI for 5'8" & 120 lbs
Result: 18.2 · Mild Thinness
Body Mass Index
18.2
Mild Thinness
WHO BMI range for this category: 17 – 18.4
What a BMI of 18.2 at 5'8" and 120 lbs means
A body mass index of 18.2 (5'8" / 120 lbs) sits just below the WHO normal cutoff. In itself it is not alarming, but combined with unexplained weight loss or fatigue it should prompt a primary-care visit.
For someone 5'8" tall, the WHO healthy BMI range (18.5 – 24.9) corresponds to a body weight between roughly 55.4 – 74.5 kg (122.1 – 164.3 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 5'8" to reach each BMI threshold
| Target BMI | Body weight | Difference vs current |
|---|---|---|
| BMI 18.5 (underweight cutoff) | 55.4 kg (122.1 lbs) | +0.9 kg |
| BMI 22 (middle of healthy range) | 65.8 kg (145.2 lbs) | +11.4 kg |
| BMI 25 (overweight cutoff) | 74.8 kg (165.0 lbs) | +20.4 kg |
| BMI 30 (obesity cutoff) | 89.8 kg (197.9 lbs) | +35.4 kg |
BMI for nearby heights and weights
Reference values at similar measurements. Each link is a pre-calculated page.
Looking for the metric equivalent? See BMI for 175 cm & 55 kg →
Frequently asked questions
- Is a BMI of 18.2 healthy for 5'8"?
- A BMI of 18.2 at 5'8" is classified as Mildly Underweight. The WHO healthy BMI range is 18.5 – 24.9, which for your height translates to roughly 55.4 – 74.5 kg (122.1 – 164.3 lbs).
- What is the ideal weight for someone 5'8" tall?
- The mid-point of the healthy BMI range (BMI 22) for 5'8" is approximately 65.8 kg (145.2 lbs). The full healthy range spans roughly 55.4 – 74.5 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 120 lbs?
- BMI does not measure body fat directly. Two people at 5'8" and 120 lbs 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 5'8" 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 5'8", 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 5'8"?
- If your BMI is below 18.5, gaining weight up to the 55.4 kg (122.1 lbs) threshold puts you in the healthy band. If above 25, losing weight toward 74.5 kg (164.3 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 5'8" and 120 lbs. For any other combination, use the full calculators below.