BMI Calculator
Check your body mass index with metric or imperial units.
Body mass index is a quick screening number that compares your weight to your height. This free BMI calculator works with metric or imperial units. Enter your height and weight to get your BMI, your weight category, and the healthy weight range for your height. It is a starting point for a conversation with a doctor, not a diagnosis. BMI does not measure body fat directly, so athletes with a lot of muscle and older adults may get a misleading number. Use it as one signal among others.
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About BMI Calculator
Body Mass Index is one of the most quoted and most misunderstood numbers in health. It reduces your body to a single ratio, weight relative to height squared, and sorts the result into familiar buckets: underweight, healthy, overweight, obese. This calculator does that arithmetic instantly, in metric or imperial units, and pairs your number with the healthy weight range for your height so you can see where you stand and what “healthy” would look like in pounds or kilograms.
The honest context matters more than the number. BMI was designed as a population screening tool, and it cannot tell muscle from fat, account for bone density, or know where on your body the weight sits. A strength athlete can land in “overweight” with very low body fat; an older adult can land in “healthy” while carrying little muscle. That's why clinicians treat BMI as a starting flag, not a verdict, and why this tool shows the healthy range alongside the category, so the number stays in perspective.
Use your result as a prompt, not a diagnosis. If the number surprises you, the productive next steps are boring and effective: measure consistently, look at the trend over weeks rather than a single reading, and bring the question to a clinician or registered dietitian if you want personal guidance. This calculator is an informational estimate only and is not medical advice.
How to use BMI Calculator
- Pick metric or imperial units.
- Enter your height and weight.
- Read your BMI, category, and healthy weight range.
- Talk to a doctor if the result worries you.
Why use this tool?
- Metric and imperial unit toggle
- Shows your healthy weight range
- Free with no signup
Tips for best results
- Weigh yourself at the same time of day, morning, after using the bathroom, for readings you can actually compare.
- Measure height barefoot, standing straight against a wall; even half an inch changes the result.
- If you lift weights seriously, treat BMI as nearly meaningless for you and look at waist circumference or body-fat estimates instead.
- Track the trend over weeks, not the single number from today; one reading is noise, a slope is information.
- Use the healthy weight range shown as a ballpark target band rather than fixating on one ideal number.