BODY MASS INDEX

BMI Calculator

Calculate your Body Mass Index using your height and weight.

For adults aged 20 and older. BMI categories are interpreted differently for children and teenagers. If you are under 20, use the CDC Child and Teen BMI Calculator instead.

Your measurements are calculated in this page in your browser; this widget does not send or save them.

About Our BMI Calculator

Our BMI Calculator helps you calculate your Body Mass Index using your height and weight. Whether you measure your height in centimeters or feet and inches, or your weight in kilograms or pounds, this online tool makes it easy to calculate your BMI.

Select your preferred measurement system, enter your measurements, and calculate your BMI to see which standard adult BMI category your result falls into. The calculator is designed for adults aged 20 and older.

BMI is a useful screening measure, but it does not provide a complete picture of your health. Consider your result alongside other health information and professional advice.

What Is Body Mass Index (BMI)?

Body Mass Index, commonly known as BMI, is a calculation that compares a person's weight with their height. It is commonly used as a screening measure to help identify weight categories that may be associated with certain health risks in adults.

BMI is calculated using height and weight, rather than a direct measurement of body fat. It does not distinguish between muscle, fat, and bone mass, so the same BMI may have different meanings for different individuals.

Important: BMI is a screening tool, not a medical diagnosis. Your result should not be used on its own to determine whether you are healthy.

How to Calculate BMI

The BMI formula uses your weight and height. The calculation method depends on the measurement units you select.

Metric BMI Formula (kg and cm)

BMI = Weight (kg) ÷ Height (m)²

Convert your height from centimeters to meters before squaring it.

US Customary BMI Formula (lb, ft and in)

BMI = 703 × Weight (lb) ÷ Height (in)²

Convert your complete height into inches by multiplying feet by 12 and adding the remaining inches.

BMI Calculation Example

Suppose an adult weighs 70 kg and is 175 cm tall.

Height in meters = 175 ÷ 100 = 1.75 m

BMI = 70 ÷ (1.75 × 1.75)

BMI = 22.9 (rounded to one decimal place)

Using standard adult BMI categories, this example falls within the healthy weight range. However, BMI alone cannot establish an individual's overall health.

BMI Chart for Adults

The following categories apply to adults aged 20 and older under standard CDC adult BMI guidance.

BMI Range (kg/m²) Adult BMI Category
Below 18.5 Underweight
18.5 to below 25 Healthy weight
25 to below 30 Overweight
30 to below 35 Obesity Class 1
35 to below 40 Obesity Class 2
40 and above Obesity Class 3

These ranges are screening categories, not individual diagnoses. A healthcare professional can help interpret your BMI in the context of your medical history, body composition, and other health measures.

Source: CDC Adult BMI Calculator and categories .

How to Use This BMI Calculator

  1. Select Metric or US Customary units.
  2. Enter your height in the fields shown.
  3. Enter your weight using the selected units.
  4. Check that your measurements are correct.
  5. Select Calculate BMI to view your result.
  6. Read the BMI category and its limitations.

For a meaningful result, use reasonably accurate height and weight measurements. You can reset the calculator and enter new measurements whenever needed.

What Can BMI Tell You?

BMI provides a standardized way to relate weight to height. It can support general health screening and help healthcare professionals decide whether further assessment may be useful.

Limitations of BMI

BMI does not directly measure body fat or show where fat is distributed in the body. It may not fully reflect health differences related to muscle mass, age, pregnancy, or individual medical circumstances.

If your BMI result concerns you, discuss it with a qualified healthcare professional rather than making medical decisions based on the calculator alone.

Can Children and Teenagers Use This BMI Calculator?

This calculator uses adult BMI categories and is intended for adults aged 20 and older. BMI is interpreted differently for children and teenagers because their bodies are still growing.

For ages 2 through 19, BMI is interpreted using age- and sex-specific BMI-for-age percentiles. Use the official CDC Child and Teen BMI Calculator for this purpose.

Frequently Asked Questions About BMI

1. What does BMI stand for?

BMI stands for Body Mass Index. It is a calculation based on weight and height that is used as a screening measure for adults.

2. How do I calculate my BMI?

Divide your weight in kilograms by your height in meters squared. For pounds and inches, multiply weight in pounds by 703 and divide by height in inches squared.

3. What is a healthy BMI for adults?

Under standard adult BMI classifications, a BMI from 18.5 to below 25 is categorized as healthy weight. This screening range does not determine an individual's overall health.

4. Can I calculate BMI using kg and cm?

Yes. Select Metric, enter weight in kilograms and height in centimeters, and calculate your BMI. The calculator uses the appropriate metric formula.

5. Can I calculate BMI using feet, inches and pounds?

Yes. Select US Customary units, enter your height in feet and inches and your weight in pounds, then calculate your BMI.

6. Is BMI an accurate measure of overall health?

BMI is useful for screening but does not directly measure body fat or diagnose disease. It should be considered alongside other health information and professional assessment.

7. Is this BMI calculator suitable for children?

No. The adult BMI categories on this page are intended for people aged 20 and older. Children and teenagers need BMI-for-age interpretation using a suitable pediatric calculator.

8. Should I speak to a healthcare professional about my BMI?

Consider seeking professional advice if you have concerns about your result or your health. A healthcare professional can assess BMI alongside your medical history and other relevant factors.

Health Information Disclaimer

This BMI calculator and its educational content are intended for general informational purposes only. The results are not a diagnosis and are not a substitute for individual medical advice, diagnosis, or treatment. Consult a qualified healthcare professional about personal health concerns.

Trusted BMI Information Sources

For additional information about BMI categories and how BMI is interpreted, consult these official health resources: