BMI calculator
Enter your height and weight to calculate your body mass index.
Toggle between metric (centimeters and kilograms) or imperial (feet, inches, and pounds) depending on what you have handy, then enter your height and weight — the BMI value and category below update instantly as you type. Both unit systems use the same underlying formula, just converted, so switching the toggle won't change your result if you enter the equivalent numbers either way.
The category label (underweight, normal, overweight, obese) comes from the standard World Health Organization ranges — see the full breakdown further down the page, along with an honest note on where BMI as a measure falls short.
The category ranges (WHO standard)
- Under 18.5 — underweight
- 18.5 – 24.9 — normal weight
- 25 – 29.9 — overweight
- 30 and above — obese
Worth being upfront about the limits here: BMI only looks at height and weight, so it can't tell muscle from fat. An athlete with low body fat can easily land in "overweight" territory just from muscle mass — the number is a population-level screening tool, not a verdict on any one person's health.
Metric or imperial — does it matter which I use?
No, the toggle above just changes the input fields; the calculation itself is identical either way.