Enter your height and weight to find your Body Mass Index and see exactly where it falls on the standard scale.
How this calculator works
This tool uses the standard BMI formula adopted by the World Health Organization: weight in kilograms divided by height in metres, squared. For someone who is 1.70 m tall and weighs 65 kg, that’s 65 ÷ (1.70 × 1.70) = 65 ÷ 2.89 = 22.5 — solidly in the normal weight range. Switch to imperial units above and the calculator converts your feet/inches and pounds to metric behind the scenes before running the same formula, so the result is identical either way.
What the ranges mean
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obese |
The “Obese” band is sometimes split further into Class I (30–34.9), Class II (35–39.9), and Class III (40+) in clinical settings, but the four-category version above is what’s used for general screening.
Where BMI falls short
BMI is a screening number, not a diagnosis. It’s calculated from height and weight alone, so it can’t distinguish muscle from fat — a muscular athlete and someone carrying excess body fat can land on the exact same BMI. It also doesn’t account for age, sex, or where fat is distributed on the body, all of which affect actual health risk. BMI charts aren’t designed for children, pregnant women, or adults over 65, and they tend to be less reliable for people who are very tall or very short. Use it as a starting point for a conversation with a doctor, not as the final word on your health.
Common questions
Is the healthy BMI range the same for men and women?
Yes — the standard 18.5–24.9 range applies to both adult men and women. Where they differ is body composition: at the same BMI, women typically carry more body fat than men, which is one reason BMI alone doesn’t tell the full story.
My BMI says “overweight” but I lift weights regularly. Should I be concerned?
Not necessarily. Because BMI can’t tell muscle from fat, athletes and people with a lot of muscle mass often score higher than their actual body fat would suggest. Waist circumference or a body fat percentage measurement gives a clearer picture in that case.
What should I do if my result is outside the normal range?
Treat it as a prompt to check in with a doctor or registered dietitian rather than a verdict. They can look at your full health picture — diet, activity, family history, and other measurements — before recommending anything.
How often should I recalculate my BMI?
For most adults, checking every few months is plenty. BMI doesn’t fluctuate meaningfully day to day, so there’s no real benefit to recalculating more often than that.
This calculator gives a general indication based on the WHO’s standard formula and isn’t a substitute for medical advice. If you have concerns about your weight or health, talk to a doctor or registered dietitian.