BMI Calculator
Calculate your Body Mass Index and see which weight category you fall into.
What is BMI?
Body Mass Index (BMI) is a simple calculation using your height and weight that estimates whether your weight falls within a healthy range. It's calculated as weight divided by height squared (metric), or weight in pounds multiplied by 703 and divided by height in inches squared (imperial). BMI is widely used by health organizations as a quick screening tool, though it doesn't directly measure body fat or account for muscle mass, bone density, or body composition.
BMI categories explained
A BMI below 18.5 is considered underweight, 18.5 to 24.9 is considered a normal weight range, 25 to 29.9 is considered overweight, and 30 or above is considered obese. These thresholds apply to most adults, though factors like age, sex, muscle mass, and ethnicity can affect how meaningful BMI is for any individual person.
Limitations of BMI
BMI doesn't distinguish between fat and muscle, so athletes and very muscular individuals may show a higher BMI without excess body fat. It's best used as a general starting point rather than a definitive health measure. This is an estimate for informational purposes only and not medical advice.
Frequently Asked Questions
Am I overweight based on my BMI?
A BMI between 25 and 29.9 typically falls into the "overweight" category, while 30 and above is classified as "obese." These are general population guidelines, though, and don't account for muscle mass, frame size, or where fat is distributed on your body — so treat it as a starting point rather than a final answer.
Is BMI accurate for muscular people or athletes?
Not always. Because BMI only uses height and weight, it can't tell the difference between muscle and fat — so athletes and heavily muscled individuals often show a "high" BMI despite having low body fat. In these cases, a body fat percentage measurement is usually more informative than BMI alone.
What's the difference between BMI and body fat percentage?
BMI is a ratio of weight to height that estimates whether your weight is in a typical range for your size. Body fat percentage directly measures how much of your body is made of fat versus lean mass. Two people with the same BMI can have very different body fat percentages depending on muscle mass and body composition.
What is a healthy weight range for my height?
A healthy weight range generally corresponds to a BMI between 18.5 and 24.9 for your height. Enter your height above and the calculator will show your estimated healthy weight range in the results breakdown, alongside your current BMI category.
Does BMI work the same way for children as adults?
No. Children and teens are assessed using age- and sex-specific BMI percentiles rather than the fixed adult categories, since body composition changes significantly during growth. This calculator is designed for adults; pediatric BMI should be evaluated using growth charts from a pediatrician.
What are the main limitations of BMI as a health metric?
BMI doesn't measure body fat directly, doesn't account for muscle mass, bone density, or fat distribution, and can be less meaningful across different ages and ethnicities. It's best used as a quick screening tool alongside other measures like waist circumference, body fat percentage, or a doctor's assessment.
How do I lower my BMI?
Since BMI is based on weight relative to height, reducing body weight through a sustainable calorie deficit combined with regular physical activity is the typical path to a lower BMI. Our calorie deficit calculator can help you find a daily calorie target for gradual, steady weight loss.