Key takeaways
- BMI Calculator works in both metric (kg/cm) and imperial (lb/in) units.
- BMI is a simple ratio of weight to height — it doesn't account for muscle mass, body composition, age, or sex.
- It's a widely used population-level screening tool, not an individual diagnosis.
- For a personal health assessment, BMI is a starting point to discuss with a doctor, not a complete picture on its own.
Calculating it
Open BMI Calculator, pick metric or imperial, enter your height and weight, and your BMI and category appear instantly.
Frequently asked questions
Is BMI accurate for athletes?
Not particularly — BMI doesn't distinguish muscle from fat, so people with high muscle mass often show a higher BMI than their actual body fat percentage would suggest.
Should I make health decisions based on BMI alone?
BMI is one data point among many that a doctor would consider — it's useful as a quick, standardized reference, not a substitute for a fuller assessment.