Enter height to see range.
Calories/day at rest.
| Underweight | < 18.5 | |
| Normal Weight | 18.5 – 24.9 | |
| Overweight | 25.0 – 29.9 | |
| Obesity | ≥ 30.0 |
Body Mass Index (BMI) is a simple screening tool used by doctors and health professionals to estimate the amount of body fat a person has. It calculates a score based on your weight in relation to your height.
While it doesn't measure body fat directly, BMI is widely used because it's a quick, non-invasive way to categorize weight and screen for potential health risks related to obesity or being underweight.
For most adults (ages 20+), BMI scores fall into standard weight categories established by the World Health Organization (WHO). Use this table to interpret your result:
| Category | BMI Range (kg/m²) | Health Risk Level |
|---|---|---|
| Underweight | Below 18.5 | Minimal / Nutrition risk |
| Normal Weight | 18.5 – 24.9 | Low Risk |
| Overweight | 25.0 – 29.9 | Increased Risk |
| Obesity Class I | 30.0 – 34.9 | High Risk |
| Obesity Class II | 35.0 – 39.9 | Very High Risk |
| Obesity Class III | 40.0 and above | Extremely High Risk |
Being overweight puts extra strain on your body. Common risks include:
Being underweight can also be dangerous:
This calculator also provides your BMR (Basal Metabolic Rate). This is the number of calories your body burns while at complete rest to maintain basic functions like breathing and digestion.
BMI is a useful screening tool, but it doesn't tell the whole story. It is not accurate for:
Not always. BMI does not distinguish between muscle and fat. Athletes with high muscle mass may have a high BMI but very low body fat. In these cases, a Body Fat Calculator is more accurate.
For most adults, a BMI between 18.5 and 24.9 is considered healthy. This range is associated with the lowest risk of weight-related health issues like diabetes and heart disease.
Standard BMI categories apply to adults 20+. For children and teens, BMI is age-and-gender specific (percentiles) because they are still growing. Older adults may also have slightly different ideal ranges.
Technically, a pound is a pound. However, muscle is much more dense than fat. One pound of muscle takes up less space than one pound of fat, which is why you can look leaner but weigh the same.
To lower BMI, you need to create a calorie deficit by eating fewer calories than you burn (BMR + Activity). Combining a balanced diet with regular exercise is the safest way to reach a healthy weight.