CALCULATORS
BMI Calculator
Calculate body mass index from weight and height as a general screening estimate.
Quick answer: Enter weight in kilograms and height in centimeters. BMI is not medical advice or a diagnosis.
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How to use BMI Calculator
- Enter weight and heightUse kilograms and centimeters.
- Read the BMIThe result shows your BMI and its standard category.
- Interpret carefullyTreat BMI as a screening number, not a diagnosis.
About this tool
BMI is a quick screening number that compares weight to height. Enter your measurements in metric or US units and see the value and its standard category.
Common uses: Get a quick BMI screening estimate for general health education, personal tracking or a conversation with a qualified clinician.
Practical example: Enter weight in kilograms and height in centimeters, then treat the result as one context point rather than a complete assessment.
Important limitation: BMI does not measure body composition and may be misleading for children, pregnancy, athletes or some medical conditions. It is not a diagnosis.
Your height and weight are used only in your browser to compute the result and are not saved. Read the privacy information.
How it works
BMI is weight in kilograms divided by height in meters squared, then mapped onto standard adult categories.
Real-world uses
- A quick general screening number
- Tracking change over time
- Discussing results with a clinician
How to use a BMI result sensibly
BMI is weight in kilograms divided by height in metres squared. The usual adult categories are under 18.5, 18.5 to 24.9, 25 to 29.9 and 30 and over. The number is easy to compute but says nothing about where weight is carried, muscle mass, age or fitness.
That is why athletes with a lot of muscle can have a high BMI without excess fat, and why older adults or people who have lost muscle can have a normal BMI with a high body fat percentage. Waist measurement, blood pressure and blood tests tell a doctor far more.
BMI categories do not apply in the same way to children and teenagers, pregnant women, or some ethnic groups, where other thresholds or growth charts are used. If the result worries you, or you are planning a change in diet or exercise, talk to a healthcare professional rather than relying on a single figure.
Tips for better results
- BMI = weight (kg) ÷ height (m)².
- BMI ignores muscle mass, age and body shape, so athletes can be misclassified.
- For children, use growth charts and guidance from a clinician.
Frequently asked questions
Is BMI medical advice?
No. It is a general screening calculation. Discuss health decisions with a qualified healthcare professional.
Can I use pounds and inches?
Convert your measurements to the units shown in the workspace before calculating.
Are my calculations uploaded?
Your height and weight are used only in your browser to compute the result and are not saved.
What is a healthy BMI range?
Commonly 18.5–24.9 for adults, but individual circumstances differ.
Is BMI accurate for athletes?
Not always. Muscle weighs more than fat, so a muscular person can have a high BMI without carrying excess body fat.
What BMI range is considered healthy?
For adults, 18.5 to 24.9 is the commonly used range, but individual health depends on much more than this single number.