A ratio, not a verdict.
Your BMI puts height and weight into one calculation. It is a useful starting point for a conversation about health.
FREE WELLNESS TOOL
Know your BMI.
See the bigger picture.
A simple check-in with your body. Enter your height and weight, then explore what your number means.
Free BMI calculator · Adults 20+
Let’s begin01 / YOUR DETAILS
Start with your measurements.
Choose the units you use every day.
No account needed. Calculated in your browser.
02 / YOUR RESULT
Your BMI, in context.
BODY MASS INDEXREADY WHEN YOU ARE
One number. A starting point.
BMI compares weight with height. It is a screening measure, not a diagnosis or a complete picture of your health.
Categories use the full calculated value. The dial illustrates BMI 10–45.
THE REFERENCE GUIDE
Understand the ranges
Standard adult categories. Your result will highlight one of these ranges.
- UnderweightBelow 18.5
- Healthy weight18.5 to below 25
- Overweight25 to below 30
- Obesity30 and above
BEYOND THE NUMBER
A little context goes a long way.
Bodies are more complex.
BMI does not distinguish muscle, fat and bone. Your history, measurements and daily habits add important context.
Make the next step personal.
Bring questions to a healthcare professional. A single number does not set your ideal weight or define your wellbeing.
A few things worth knowing.
How is BMI calculated?
BMI is weight in kilograms divided by height in meters squared: kg ÷ m². We convert pounds and feet to metric units before calculating.
Can children and teenagers use this tool?
This calculator uses categories for adults aged 20 or older. Children and teens need an age- and sex-specific assessment. Use the CDC child and teen calculator.
What if I am muscular or pregnant?
Muscle can affect the meaning of a BMI result because BMI does not separate muscle from fat. This tool is not suitable during pregnancy. Ask your healthcare professional which measures are appropriate for you.
Does this tell me whether I am healthy?
No. BMI is one screening measure. It should be considered with medical history, physical examination and other information. Discuss your result with a qualified healthcare professional.
Formula and adult ranges: CDC adult BMI categories · About BMI. See also NHS calculator guidance.
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