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How to Interpret Your BMI and Waist Circumference Numbers

This page is general information to help you understand BMI and waist circumference results and is not a substitute for medical diagnosis. If you need to manage your weight, talk with a doctor.

  1. How BMI is calculated

    Body mass index (BMI) is your weight in kilograms divided by your height in meters, squared. For example, someone who is 170 cm (1.7 m) tall and weighs 70 kg has a BMI of about 70 Γ· (1.7 Γ— 1.7) β‰ˆ 24.2.

  2. Common BMI classification ranges

    The World Health Organization's global standard generally treats under 18.5 as underweight, 18.5 to 24.9 as normal, 25 to 29.9 as overweight, and 30 or above as obese. Many countries in Asia use an Asia-Pacific classification with lower cutoffs instead β€” roughly 23 for overweight and 25 for obese β€” since health risk appears to rise at a lower BMI in Asian populations on average. Always check which standard your own results sheet is using.

  3. The key limitation of BMI

    Because BMI is calculated purely from height and weight, it doesn't directly measure body fat. Someone with a lot of muscle mass can have a high BMI despite low body fat, while someone with low muscle mass (sometimes called 'skinny fat') can have a normal BMI despite a relatively high body fat percentage.

  4. Waist circumference thresholds for abdominal obesity

    Commonly used thresholds classify a waist circumference of about 90 cm (about 35 in) or more in men, and about 85 cm (about 33 in) or more in women, as abdominal obesity, though the exact cutoff varies somewhat by country and population. It's typically measured at the level of the navel, at the end of a relaxed exhale.

  5. Why waist circumference is checked separately

    Even at the same BMI, a body shape with more visceral (abdominal) fat is associated with a higher risk of metabolic conditions like type 2 diabetes, high blood pressure, and abnormal cholesterol levels. That's why health checkups often look at BMI and waist circumference together rather than relying on either alone.

  6. How to interpret the results together

    Don't assume everything is fine just because BMI looks normal β€” check your waist circumference too, and if both numbers are outside the typical range, it's worth reviewing diet and exercise habits. Weight-management goals and methods vary by individual health status, so it's a good idea to involve a doctor if you need guidance.

Try calculating your own numbers

Plugging your own height and weight into the BMI formula above, and measuring your waist circumference with a tape measure, takes just a couple of minutes and turns these classification ranges from abstract numbers into something concrete about your own body.

Why it's worth tracking both

A normal BMI doesn't rule out higher metabolic risk if your waist circumference is elevated, since abdominal fat carries its own risk independent of overall weight. Getting into the habit of checking both together gives you a more complete picture of how your body composition is changing over time.

Frequently Asked Questions

I exercise a lot and have more muscle, but my BMI came back as overweight β€” is that a problem?

Not necessarily. Because BMI doesn't directly measure body fat, higher muscle mass can push BMI up regardless of your actual body fat level. In that situation, a body composition analysis or your waist circumference gives a more accurate picture than BMI alone.

What's the correct way to measure waist circumference?

The generally recommended method is to wrap a tape measure horizontally around your body at the level of your navel, and take the measurement after exhaling comfortably, not sucking in or forcing a deep breath.