BMI Calculator — Body Mass Index from Height and Weight
Quickly calculate your body mass index
| BMI range | Category | Description |
|---|---|---|
| < 18.5 | Underweight | Too low — increase your nutrition intake |
| 18.5 - 24.9 | Normal weight | Normal — keep a healthy lifestyle |
| 25.0 - 29.9 | Overweight | Above the healthy range — exercise moderately and watch your diet |
| ≥ 30.0 | Obese | Well above the healthy range — consult a doctor |
About BMI
BMI (Body Mass Index) is a person’s weight in kilograms divided by the square of their height in meters. It is a widely used international standard for gauging body weight and health. This tool quickly computes your BMI to help you see whether your weight is in the normal range; for specific health concerns, consult a doctor.
More Tools
When tracking body metrics, use Food Calories to learn about dietary energy, or Water Intake Calculator to estimate your daily water needs.
FAQ
What is BMI and how is it calculated?
BMI (Body Mass Index) is a widely used international measure of body weight relative to height. Formula: BMI = weight (kg) ÷ height (m)². For example, at 170 cm and 65 kg the BMI is 22.5.
What is the normal BMI range?
By Chinese standards: BMI < 18.5 is underweight, 18.5 ≤ BMI < 24 is normal, 24 ≤ BMI < 28 is overweight, and BMI ≥ 28 is obese. This tool computes it automatically and gives the matching weight-category advice.
Does BMI apply to everyone?
Athletes (high muscle mass raises BMI), pregnant and breastfeeding women, minors, the elderly and other groups with high muscle mass or specific physiological stages should assess their condition with additional metrics such as body-fat percentage and waist circumference.
What is the difference between BMI and body-fat percentage?
BMI considers only height and weight and cannot distinguish muscle from fat. Body-fat percentage directly measures the proportion of body fat and reflects obesity more accurately — people with the same BMI can have very different body-fat percentages. To estimate a child’s growth, see the Child Height Predictor.