BMI Calculator
Body Mass Index (BMI) is the world’s most-used quick screen for weight status — one number from your height and weight that places you in a standard category. It isn’t perfect (it can’t tell muscle from fat), but it’s a useful starting point.
BMI is a screening tool, not a diagnosis. Muscular people often land in “overweight” while being very lean.
The BMI formula
BMI categories (WHO)
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25 – 29.9 | Overweight |
| 30 and above | Obese |
What BMI doesn’t tell you
BMI can’t distinguish muscle from fat, so lifters and athletes often score “overweight” while carrying little body fat. Pair it with our body fat calculator and waist-to-hip ratio for a fuller picture.
Frequently asked questions
What is a good BMI?
The World Health Organization defines 18.5–24.9 as the healthy range for most adults.
Is BMI accurate?
It’s a decent population-level screening tool but a rough individual measure — it ignores muscle mass, bone density, and fat distribution.
Why is my BMI high if I’m muscular?
Muscle is denser than fat, so muscular people weigh more at the same size. If you lift regularly, body fat percentage is a better metric.
Does BMI differ by age or sex?
The standard adult cutoffs are the same for men and women. For children and teens, BMI is interpreted with age-and-sex percentiles instead.
How can I lower my BMI?
A sustained modest calorie deficit plus resistance training 2–4 times per week lowers BMI while preserving muscle — check your targets with our TDEE calculator.