BMI Calculator
Calculate Body Mass Index with healthy weight range, category breakdown, and session history.
Free & unlimited
Unit system
Height (cm)
Weight (kg)
Age (optional)
Sex (optional)
Enter your height and weight to calculate BMI.
All processing happens in your browser. No data is sent to any server.
About this tool
- 1
Choose your unit system
Switch between metric (kg/cm) and imperial (lbs/inches) input.
- 2
Enter your measurements
Input your weight and height in the selected units.
- 3
View your BMI
See your BMI value with the WHO category (underweight, normal, overweight, obese) on a color-coded scale.
- BMI is a screening tool, not a diagnosis - it does not account for muscle mass, bone density, or fat distribution.
- For athletes and muscular individuals, BMI often overestimates body fat.
- A normal BMI range is 18.5 to 24.9 according to the WHO classification.
- Consider waist circumference as a complementary metric - it better predicts health risks from abdominal fat.
- Metric and imperial unit support
- Visual color-coded BMI scale
- WHO category classification
- Healthy weight range display for your height
- BMI prime ratio calculation
- Get a quick general health screening metric.
- Track BMI changes over time during a fitness program.
- Calculate BMI for medical forms and health assessments.
- Understand the healthy weight range for a given height.
WHO categories: Underweight < 18.5, Normal 18.5-24.9, Overweight 25-29.9, Obese class I 30-34.9, Obese class II 35-39.9, Obese class III 40+.
No. BMI does not distinguish between muscle and fat. Athletes may have a high BMI despite low body fat. It is also less reliable for children, elderly, and pregnant individuals.
BMI prime is your BMI divided by 25 (the upper limit of normal). A BMI prime of 1.0 means you are at the upper edge of normal weight. Below 1.0 is normal; above is overweight.