Adult BMI Calculator
Calculate your Body Mass Index and understand what your result may mean.
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Your health guidance
What Is BMI?
Body Mass Index (BMI) is a screening measurement calculated from your weight and height. For adults, BMI can help classify weight status, but it does not directly measure body fat and should not be used by itself to diagnose a health condition.
The adult BMI calculation uses weight in kilograms divided by height in metres squared.
Adult BMI Categories
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25.0 – 29.9 | Overweight |
| 30.0 – 34.9 | Obesity Class I |
| 35.0 – 39.9 | Obesity Class II |
| 40.0 or higher | Obesity Class III |
How Your BMI Result Should Be Used
BMI is a useful screening measure, but it is only one part of assessing health. Your waist circumference, medical history, blood pressure, blood tests, physical activity, diet, medications and other factors can also be important.
Why BMI Is Not a Diagnosis
BMI cannot distinguish between muscle, bone and fat mass. A muscular person may have a higher BMI without having excess body fat. Older adults and people with certain medical conditions may also require a more individualized assessment.
Healthy Weight Range
This calculator also estimates the weight range corresponding to a BMI of 18.5 to 24.9 for your entered height. This is a mathematical reference range, not a personal medical target.
Frequently Asked Questions
What is a healthy BMI for adults?
For adults, a BMI from 18.5 to 24.9 is generally classified as healthy weight using standard adult BMI categories.
Is BMI the same for men and women?
Standard adult BMI categories use the same BMI cutoffs for men and women. Sex is collected here because a broader health assessment may require additional sex-specific considerations.
Can BMI be used for children?
Children and teenagers should not be interpreted using the adult BMI categories on this calculator. Their BMI must be interpreted according to age and sex using BMI-for-age growth charts.
Does BMI measure body fat?
No. BMI is calculated from height and weight and is a screening measure. It does not directly measure body fat.
What should I do if my BMI is high?
Do not use BMI alone to make a diagnosis. Consider discussing your result with a qualified healthcare professional, especially if you have other health concerns or risk factors.
What if my BMI is below the healthy range?
A low BMI can have different causes. If you have unexplained weight loss, poor appetite, weakness or other symptoms, speak with a healthcare professional.
