BMI at 175 cm and 50 kg — 16.3 (Underweight)
A BMI of 16.3 at 175 cm and 50 kg falls in the Underweight category under the World Health Organization's classification. The calculation is straightforward — 50 kg divided by your height in metres squared — and this page shows every step, the healthy weight range for 175 cm (56.7–76.3 kg), and what the number does and does not mean for you.
At 16.3, this BMI sits below the healthy range. That can happen for many reasons — a naturally slight build, recent illness, a very active lifestyle with low body fat, or not eating enough. It is not a diagnosis, and on its own it does not say whether a person is healthy. What it does say is that the number is worth a conversation with a healthcare professional, especially if weight has dropped recently or without trying.
Remember what this page is: an estimate from a screening tool, not medical advice and not a diagnosis. BMI was designed for population studies, and it works best when it is read alongside other measures — waist circumference, body-fat percentage, blood pressure and how active you are. The sections below give you those next steps.
Calculate your own BMI
Use the BMI calculator to work out your own BMI at any height and weight. Enter your measurements and the tool applies the same formula shown below, with your WHO category. If you also want an estimate of body fat, try the body fat calculator.
Related pages in this section:
The formula, shown and cited
BMI is defined by the World Health Organization as weight in kilograms divided by height in metres squared:
BMI = weight (kg) ÷ height (m)²
Worked through for this page:
- Height: 175 cm = 1.75 m
- Height squared: 1.75 × 1.75 = 3.0625 m²
- Weight: 50 kg
- Calculation: 50 ÷ 3.0625 = 16.3
The WHO categories are: underweight below 18.5, healthy weight 18.5–24.9, overweight 25.0–29.9, and obese 30 and above. At 16.3, this result is Underweight. The same formula applies to every adult; the categories are the same for men and women, though the interpretation can differ with age, muscle mass and ethnicity, which is one more reason to treat the number as a starting point rather than a verdict.
BMI at 175 cm across weights
| Weight | BMI | Category |
|---|---|---|
| 50 kg | 16.3 | Underweight |
| 60 kg | 19.6 | Healthy Weight |
| 70 kg | 22.9 | Healthy Weight |
| 80 kg | 26.1 | Overweight |
| 90 kg | 29.4 | Overweight |
| 100 kg | 32.7 | Obese |
| 110 kg | 35.9 | Obese |
| 120 kg | 39.2 | Obese |
| 130 kg | 42.4 | Obese |
| 140 kg | 45.7 | Obese |
This table shows how sensitive BMI is to weight at a fixed height: every 10 kg moves the BMI by about 3.3 points at 175 cm. It also shows why a single BMI number is more useful inside a range than on its own — the healthy range for this height spans 56.7 kg to 76.3 kg, a spread of 19.6 kg.
The healthy weight range at 175 cm
| Boundary | BMI | Weight |
|---|---|---|
| Bottom of healthy range | 18.5 | 56.7 kg |
| Top of healthy range | 24.9 | 76.3 kg |
| Your weight | 16.3 | 50 kg |
Reaching the healthy range at 175 cm means weighing between 56.7 kg and 76.3 kg — a gain of about 6.7 kg from 50 kg to reach the bottom of the range. Any weight gain should be gradual, built on regular meals with enough protein and energy, and ideally discussed with a healthcare professional or dietitian rather than attempted alone.
What the number does NOT tell you
BMI cannot tell muscle from fat, and that is its central limitation. A rugby player and a sedentary office worker can share the same BMI and have completely different body compositions and health risks. BMI also says nothing about where fat is carried: fat around the waist (visceral fat) carries more health risk than fat on the hips and thighs, which is why waist circumference is the most useful companion measure — a waist above 94 cm for men or 80 cm for women is a commonly used flag for increased risk, whatever the BMI. BMI does not measure fitness, blood pressure, blood sugar or cholesterol, and it is less reliable for older adults (who may have lost muscle), for very tall or short people, and for some ethnic groups. None of this makes BMI useless — it makes it a first step. If your BMI is outside the healthy range, the right response is to gather the other measures and talk to a healthcare professional, not to panic or to crash-diet.
How to use the result
Start with a waist measurement: a tape around the narrowest point of your torso, or at the navel if that is easier to find consistently. Then consider a body-fat estimate — the Navy method needs only a tape measure and gives a figure with an error of about ±3–4 percentage points. Together, BMI, waist and body fat give a much fuller picture than any one of them alone. If you decide to change your weight, set a process goal rather than a number goal: a daily walk, a regular strength session, a consistent meal pattern. Weigh yourself no more than once a week, at the same time of day, and judge progress over a month, not a day. And if your BMI is in the obese range, or you have other health concerns such as diabetes, high blood pressure or joint pain, involve a healthcare professional before starting a weight-loss plan — they can check the things BMI cannot see.
Frequently asked questions
Is a BMI of 16.3 at 175 cm and 50 kg healthy?
By the WHO categories, 16.3 is underweight. That is outside the healthy range of 18.5–24.9, which runs from 56.7 kg to 76.3 kg at this height. But BMI is a screening tool, not a diagnosis — it cannot tell muscle from fat, so a muscular person can score high and a person with low muscle can score in the healthy range. Use it alongside waist measurement and, if useful, a body-fat estimate.
What is the healthy weight range at 175 cm?
Between 56.7 kg and 76.3 kg — the weights that give a BMI of 18.5 and 24.9 at 175 cm. At 50 kg, this page's BMI is 16.3. The range is a guide, not a target you must hit exactly; many healthy people sit near its edges.
How is BMI calculated for 175 cm and 50 kg?
BMI = weight in kilograms divided by height in metres squared. Here that is 50 ÷ (1.75 × 1.75) = 50 ÷ 3.0625 = 16.3. The formula is the same for every adult; only the numbers change.
Can BMI be wrong for muscular people?
Yes — this is BMI's best-known limit. Muscle is denser than fat, so a muscular person can have a BMI in the overweight or obese range with very little body fat. That is why the WHO describes BMI as a screening tool: it flags people to look at more closely, and the follow-up should include waist circumference and, where useful, a body-fat estimate.
Should I try to change my BMI quickly?
No. Aim for a gradual change of 0.5–1% of body weight per week, through sustainable eating and activity changes. Very fast weight loss usually means lost muscle as well as fat, and very-low-calorie diets carry real risks. Keep daily intake above 1,200 kcal (women) or 1,500 kcal (men) and talk to a healthcare professional before any major change.
Estimates only, not medical advice. Minimum safe intakes: 1,200 kcal/day women, 1,500 kcal/day men — consult a healthcare professional before a very-low-calorie diet.