About This Tool
Calculate your Body Mass Index (BMI) using the standard WHO formula: weight (kg) divided by height (m) squared. Supports both metric (kg/cm) and imperial (lb/in) units. The calculator displays your BMI value, the WHO weight category (underweight, normal, overweight, obese), and your healthy weight range based on your height.
Frequently Asked Questions
- How is BMI calculated?
- BMI = weight (kg) / height (m)². For imperial units, the formula is BMI = 703 × weight (lb) / height (in)². A BMI of 18.5–24.9 is considered normal weight by the WHO.
- Is BMI accurate for athletes or muscular people?
- BMI doesn't distinguish between muscle and fat mass. Athletes with high muscle mass may show an 'overweight' BMI despite having low body fat. For a more complete picture, consider body fat percentage or waist-to-hip ratio.
- What are the BMI categories?
- WHO categories: Underweight (< 18.5), Normal weight (18.5 – 24.9), Overweight (25.0 – 29.9), Obese Class I (30.0 – 34.9), Obese Class II (35.0 – 39.9), Obese Class III (≥ 40.0).
- Does BMI apply to children?
- This calculator uses the adult BMI formula. For children and teens (ages 2-20), BMI is interpreted using age- and sex-specific percentile charts, which this tool does not include.