Free BMI Calculator for Adults
Use this free BMI calculator to estimate your body mass index based on your height and weight.
BMI is a screening measurement that compares weight with height. It can provide a general starting point, but it does not diagnose health conditions or measure body fat directly.
The calculator may take a few moments to load. Please wait for it to appear before entering your information.
Calculate Your BMI
Enter your height and weight to calculate your estimated BMI. You can usually choose between metric and imperial units.
The calculator may show:
- Your estimated BMI
- Your general BMI category
- The formula used for the calculation
- General information about what your result may mean
Your result is an estimate. It should not be treated as a diagnosis or a complete assessment of your health.
What Is BMI?
BMI stands for body mass index. It is calculated using your weight and height.
For metric measurements:
BMI = weight in kilograms ÷ height in meters squared
For imperial measurements:
BMI = 703 × weight in pounds ÷ height in inches squared
BMI is commonly used as a screening tool for adults. It does not account for every factor that affects health.
Adult BMI Categories
For adults, standard BMI categories are:
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 to 24.9 | Healthy weight range |
| 25.0 to 29.9 | Overweight |
| 30.0 or higher | Obesity range |
These categories are general screening ranges. They do not tell you whether you are healthy or unhealthy on their own.
A person’s muscle mass, body composition, age, medical history, and other factors can affect how BMI should be interpreted.
What Your BMI Result Means
Your BMI result can help you start a conversation about your health. It should be considered alongside other information, such as:
- Waist measurement
- Blood pressure
- Blood sugar
- Cholesterol
- Physical activity
- Diet
- Sleep
- Family history
- Medical conditions
A BMI result outside the general range does not automatically mean that you need to lose or gain weight. A qualified health professional can help you understand your result in context.
BMI Limitations
BMI has several important limitations.
It does not directly measure:
- Body fat percentage
- Muscle mass
- Bone density
- Fat distribution
- Fitness level
- Overall health
For example, people with a high amount of muscle may have a higher BMI without having excess body fat. Older adults may also need a more detailed health assessment than BMI alone can provide.
BMI is also not designed to assess children and teenagers using adult categories. Children and teens need age- and sex-specific growth charts.
Who Should Not Use Adult BMI Categories?
Speak with a qualified health professional instead of relying on this calculator if you:
- Are under 20
- Are pregnant
- Recently gave birth
- Have a history of an eating disorder
- Are a competitive athlete
- Have a medical condition that affects weight
- Take medication that affects your weight or appetite
- Have experienced sudden or unexplained weight changes
How to Use Your BMI Result
Use your result as general information, not as a strict health goal.
You can support your overall health by:
- Eating a variety of nutrient-rich foods.
- Including protein and fiber in regular meals.
- Drinking water and other low-calorie beverages.
- Choosing physical activities you can maintain.
- Getting enough sleep.
- Avoiding extreme diets or rapid weight-loss promises.
- Discussing concerns with a doctor or registered dietitian.
Tea can fit into a balanced eating pattern. Unsweetened tea is usually low in calories, but tea alone does not guarantee weight loss.
Read more:
- Free Calorie Calculator for Weight Loss
- Can Tea Help You Lose Weight?
- Green Tea and Weight Loss
- How to Drink Tea Without Adding Extra Calories
- Weight Loss Tea Ingredients to Avoid
Frequently Asked Questions
What is a healthy BMI?
For adults, a BMI from 18.5 to 24.9 is commonly classified as the healthy weight range. This is a general screening category, not a complete measure of health.
Is BMI accurate?
BMI can be useful as a general screening tool, but it is not accurate for everyone. It does not separate muscle from fat or show where fat is stored in the body.
What BMI is considered overweight?
For adults, a BMI from 25.0 to 29.9 is commonly classified as the overweight range. A health professional can help interpret this result based on your complete health history.
What BMI is considered obesity?
For adults, a BMI of 30 or higher is commonly classified within the obesity range. BMI alone does not diagnose a health condition.
Can I use this calculator for children?
No. Adult BMI categories should not be used for children and teenagers. Their BMI is interpreted using age- and sex-specific growth charts.
Can BMI tell me how much I should weigh?
BMI can show a general weight range based on height, but it cannot determine an ideal weight for every person. Muscle mass, age, body composition, and health history also matter.
Important Safety Information
This calculator provides general educational information. It does not diagnose, treat, or prevent any health condition.
Do not make major changes to your diet or exercise routine based only on a BMI result. Speak with a doctor, registered dietitian, or other qualified health professional if you have concerns about your weight or health.
