BMI Calculator

Calculate your Body Mass Index for free, with healthy weight range, BMI Prime, and Ponderal Index. Adults 20 and older.

Units
ft
in
Your BMI
22.5kg/m²
Normal

BMI between 18.5 and 24.9 is generally associated with the lowest risk of weight-related health conditions.

BMI is a screening measure, not a diagnosis. Results are educational and do not replace a clinician’s assessment.

What BMI actually measures

Body Mass Index (BMI) is a screening tool that estimates whether your weight falls within categories such as underweight, normal weight, overweight, or obesity based on your height and weight. BMI is widely used in public health, primary care, insurance assessments, and weight management programs.

BMI does not directly measure body fat, muscle mass, or overall health, but it can help identify potential weight-related health risks when used alongside other factors like waist circumference, activity level, blood pressure, and metabolic health.

This BMI calculator estimates your Body Mass Index using standard adult BMI categories commonly used in the United States.

Related weight management and wellness guides

BMI categories are often used to estimate risk for conditions like type 2 diabetes, high blood pressure, sleep apnea, cardiovascular disease, and metabolic syndrome. However, athletes and people with higher muscle mass may have elevated BMI values without excess body fat.

Weight management is influenced by many factors including sleep, stress, hormones, physical activity, medications, nutrition, genetics, and long-term lifestyle habits. Sustainable changes tend to produce better long-term outcomes than short-term restrictive dieting.

Want to estimate your daily calorie needs too? Use our TDEE calculator to estimate calorie expenditure based on your body size and activity level.

Questions about BMI, weight loss, or metabolic health?

august is a private AI health companion that can help explain BMI categories, calorie needs, metabolism, nutrition, exercise, weight management, and healthy lifestyle habits without a clinic visit or copay.

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Frequently Asked Questions

For most adults a BMI between 18.5 and 24.9 is considered the healthy range. It is a guide for population-level risk, not a strict target for every individual.

BMI is your weight in kilograms divided by your height in metres squared. The calculator handles the conversion automatically whether you enter metric or US units.

Not always. BMI cannot separate muscle from fat, so very muscular people can read as overweight even with low body fat. Pair it with other measures like waist size or body composition.

Childhood and teen BMI is read against age and sex growth percentiles, not the adult categories. For anyone under 20, treat this result as a rough guide and check with a clinician.

BMI Prime is your BMI divided by 25, the upper limit of the healthy range. A value below 1 sits inside the healthy range, and a value above 1 shows how far you are over it.

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