BMI Calculator
BMI, or Body Mass Index, is a quick screening tool that compares your weight to your height. It is widely used in public health because it is simple, inexpensive, and reasonably useful for flagging patterns of risk across large groups of people. Higher BMI levels are associated with elevated risk for several chronic diseases, and very low BMI can also signal health concerns. That said, BMI has limits. It does not separate muscle from fat, so athletic or muscular people can score as overweight without carrying excess body fat. It also does not account for differences in age, ethnicity, body fat distribution, or bone structure. That does not make BMI useless. It just means it works best as a starting point rather than a full diagnosis. Use it to get context, then combine it with other information such as waist size, body fat percentage, blood markers, and how you feel and function day to day.
For informational purposes only
This calculator provides estimates based on established scientific formulas. Results are not medical or nutritional advice. Individual needs vary. Consult a registered dietitian or healthcare provider before making significant dietary changes, especially if you have a medical condition.
Height and weight
Enter your height and weight to calculate BMI instantly.
BMI categories
Enter your height and weight to calculate BMI.
BMI is a useful screening tool but has limitations.
It doesn't account for muscle mass, bone density, or fat distribution. Athletes and muscular individuals often have high BMI despite being healthy. Use body fat percentage alongside BMI for a fuller picture.
Check your body fat percentage →Frequently asked questions
What is a healthy BMI range?
For most adults, a BMI between 18.5 and 24.9 is considered the normal or healthy range. Below 18.5 is classified as underweight, 25 to 29.9 as overweight, and 30 or above as obesity. These cutoffs are useful screening thresholds, not a complete judgment of health.
Is BMI an accurate measure of health?
BMI is accurate for what it is designed to do: provide a quick height-to-weight screening metric. It can correlate with health risk at the population level, but it does not directly measure body fat, muscle mass, or fitness. It is most useful when combined with other markers.
Why does BMI differ for men and women?
The BMI formula itself does not change between men and women, but average body composition often does. Women usually carry a higher essential body fat percentage than men, and men are more likely to have more lean mass at the same BMI. That is one reason BMI should be interpreted carefully.
What is the BMI formula?
In metric units, BMI equals weight in kilograms divided by height in meters squared. In imperial units, the formula is weight in pounds divided by height in inches squared, multiplied by 703. Both methods give the same result when converted correctly.
Can you be obese by BMI but still be healthy?
It is possible for some people to have a high BMI and still show strong fitness markers, good blood pressure, and healthy lab work, especially if they carry more muscle. Even so, BMI in the obese range should be a prompt to look deeper at body composition, waist circumference, and other health data rather than ignore it outright.