BMI Calculator
Quickly check your current weight status with the Body Mass Index (BMI).
Input Information
Result
Easily check your health status with BMI (Body Mass Index)!
BMI (Body Mass Index) is the most common health indicator for estimating body fat from height and weight. Standardized by the WHO, this value is used worldwide to quickly see whether a person's weight is within a healthy range. It is also used in health checkups in Korea, so you can set a starting point for health management with just two simple numbers.
The BMI calculator is easy for anyone—office workers, students, homemakers—to use. Especially for those starting a diet or interested in health management, it is the first step to objectively understand your current state. Check your weight status at home without going to a hospital or gym.
However, BMI has limits: it does not reflect muscle mass, body shape, frame, age, or sex. For muscular athletes or the elderly, BMI alone makes an accurate health judgment difficult, so use BMI as a supporting indicator and always consult a professional for accurate health assessment.
Term Glossary
- BMI (Body Mass Index)
- An indicator estimating body fat from height and weight: weight(kg) divided by height(m) squared. A basic health metric used worldwide.
- WHO (World Health Organization)
- The international public-health body that standardized BMI classification (underweight, normal, overweight, obese) globally. Korea's health-checkup criteria follow it.
📋 How to Use
- 1Enter height → input your height in cm (e.g. 170cm)
- 2Enter weight → input your weight in kg (e.g. 65kg)
- 3Calculate BMI → click the Calculate button
- 4View results → check your BMI score and weight classification (underweight/normal/overweight/obese)
📝 Worked Examples
Example 1: 170cm, 65kg
BMI = 65 ÷ (1.70)² = 65 ÷ 2.89 = 22.49Result: Normal (18.5~24.9)
Example 2: 160cm, 80kg
BMI = 80 ÷ (1.60)² = 80 ÷ 2.56 = 31.25Result: Obese (Class 2) (30.0+)
BMI formula and how it works
Basic formula: BMI = weight(kg) ÷ height(m)²
Convert height to meters, square it, then divide weight by it to get BMI.
Example: height 175cm (1.75m), weight 70kgBMI = 70 ÷ (1.75)² = 70 ÷ 3.0625 ≈ 22.9 → NormalWHO BMI classification table
- Below 18.5: Underweight (watch for malnutrition)
- 18.5 ~ 24.9: Normal weight (healthy range)
- 25 ~ 29.9: Overweight (obesity stage 1)
- 30 ~ 34.9: Obese (stage 2, health management needed)
- 35 and above: Severe obesity (stage 3, see a specialist)
💡 Tips for using BMI correctly
1. Don't judge health by BMI alone
Muscular athletes may show a high BMI, but that is due to muscle, not body fat. It is important to consider waist circumference, body-fat percentage, and blood-test results together with BMI.
2. Consider age and sex differences
The same BMI can carry different health risks by age and sex. Especially for those 65+, maintaining an appropriate weight matters more for health, and attention to muscle loss is needed.
3. Also check waist circumference
Even within a normal BMI, abdominal obesity (waist ≥ 90cm male, ≥ 85cm female) raises the risk of metabolic syndrome, diabetes, and cardiovascular disease, so measure waist circumference too.
4. Lifestyle habits to improve BMI
Combine a balanced diet with regular exercise and keep a balance between daily calories consumed and burned. Enough sleep (7~8 hours) and stress management also help greatly with weight control.
5. Regular BMI monitoring matters
BMI is not one-and-done; measuring periodically to observe trends is effective. Check regularly 1~2 times a month and reflect it in diet and exercise adjustments.
6. Children and teens differ from adults
A child's or teen's BMI is evaluated by relative position (percentile) among same-age, same-sex children, unlike adults. Consult a pediatrician appropriate to the growth stage.
7. Set realistic BMI goals
Losing even 5~10% of your current BMI yields large health benefits, so aim for small, steady changes rather than extreme loss.
❓ Frequently Asked Questions
QDoes BMI account for muscle mass?
No, BMI only considers weight and height. Athletes with high muscle mass may be classified as overweight despite low body fat.
QHow do BMI standards differ?
WHO standards: Underweight <18.5, Normal 18.5-24.9, Overweight 25-29.9. Asian populations may use lower thresholds (Overweight ≥23).
QDoes it apply to children?
Not directly. Children use BMI-for-age percentile charts that account for growth patterns.
QWhat about body type differences?
Same BMI can differ in body composition. Muscular vs sedentary individuals have different health risks at the same BMI.
QWhat other indicators should I check alongside BMI?
Waist circumference, body fat percentage, blood pressure, and blood lipids together provide better health assessment.