Free online BMI calculator. Enter your height and weight to get your Body Mass Index and WHO classification, plus your healthy weight range
Enter your height and weight and the BMI value updates immediately - no button to press
Results are grouped into underweight, healthy, overweight and obese using WHO international adult standards
See the weight range (kg) that corresponds to a healthy BMI for your exact height
A color-coded scale from 15 to 40 shows where your score falls at a glance
Limitations are explained up front: the tool is for general adults and not for children, pregnancy or athletes
Everything runs in your browser - no uploads, no sign-up, and your numbers stay on your device
Stand straight without shoes to measure your height in centimeters, and weigh yourself on an empty stomach in the morning in kilograms, e.g. 175 cm and 70 kg.
Type your height and weight into the two fields. Integers and decimals are supported and input is validated automatically.
The tool shows your BMI number, a color-coded category badge and a marker on the BMI scale so you can see which band you fall into.
A healthy weight range in kilograms for your height is shown below the scale - useful as a goal or reference for weight management.
Track your BMI between check-ups to see how your weight status is trending over time
Use the healthy weight range to translate "get to a healthy BMI" into a concrete target weight
Gyms and weight-loss programs use BMI alongside body fat as a baseline metric for progress
Corporate wellness programs and insurance applications often reference BMI as a screening metric
Adults in a household can track BMI together to stay aware of gradual weight changes
Population health programs use BMI distribution as a baseline for nutrition and exercise interventions
BMI (Body Mass Index) estimates body size from height and weight using the formula BMI = weight (kg) ÷ height (m)². Introduced in the 19th century, it remains the most common screening metric for adult weight status because it is non-invasive, cheap and easy to compare across large groups.
WHO international adult categories: below 18.5 is underweight; 18.5-24.9 is healthy weight; 25-29.9 is overweight; 30 or above is obese, often divided into further obesity classes. Some national bodies use lower cut-offs for Asian populations because the same BMI can carry a higher body fat percentage.
BMI does not separate muscle from fat, so athletes can be misclassified as overweight and older adults with low muscle mass can have a normal BMI despite excess fat. It should not be used for growing children, pregnant women or very elderly adults. Combine BMI with waist circumference, body fat percentage and clinical measures for a reliable picture.
If your BMI is above the healthy band, aim for gradual weight loss of about 0.5-1 kg per week through balanced nutrition, regular activity and a modest calorie deficit. If you are underweight, increase energy and protein intake and add strength training. Lasting change comes from habits, so consider speaking with a doctor or dietitian rather than crash dieting.