BMI Calculator
Calculate your Body Mass Index (BMI). Enter your height and weight to see your BMI and its standard category. This is a general screening estimate, not medical advice.
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Check it outWhat BMI does and doesn't tell you
BMI is a quick screening number that relates weight to height. The standard categories are: under 18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, and 30+ obese. It doesn't distinguish muscle from fat, so very muscular people can read high. Treat it as a rough indicator and talk to a healthcare professional about your individual health.
How it’s calculated
BMI = 703 × weight (lb) ÷ height (in)². Categories: under 18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, 30+ obese.
Results update as you type and are estimates, not professional advice — verify important decisions with a qualified professional.
Sources: CDC / WHO BMI categories.
Worked example
A person 5'10" and 170 lb has a BMI of about 24.4, in the normal range.
Common mistakes
- Treating BMI as body fat — it ignores muscle.
- Using it as a diagnosis rather than a screening number.
Where it is used
- A quick general health screening.
- Tracking BMI alongside other measures.
Frequently asked questions
Is BMI accurate for everyone?
No — it can overstate body fat for muscular people and understate it for others. It's a population screening tool, not a diagnosis.
What's a healthy BMI?
The 'normal' range is generally 18.5–24.9, but healthy weight varies by person. Discuss your situation with a professional.
How do I convert to metric?
BMI = weight (kg) ÷ height (m) squared. This tool uses the imperial formula (703 × lbs ÷ in²).
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