BMI Calculator
Use this free BMI calculator to check your Body Mass Index using your height and weight. Get your BMI score, adult weight category, and estimated healthy weight range in seconds.
Check Your BMI
Enter your height and weight below to calculate your BMI.
Free BMI Calculator
A BMI calculator helps estimate whether your weight is in a commonly used adult weight category based on your height. BMI stands for Body Mass Index. It is widely used as a simple screening number for adults, but it should not be treated as a complete health diagnosis.
What Is BMI?
BMI is a calculated measure of body weight relative to height. It gives a number that can be compared with standard adult BMI categories such as underweight, healthy weight, overweight, and obesity.
BMI Formula
Metric Formula
BMI = weight in kg / height in meters²
US Formula
BMI = 703 × weight in pounds / height in inches²
Adult BMI Categories
| BMI Range | Weight Category | What It May Mean |
|---|---|---|
| Below 18.5 | Underweight | Your weight may be below the commonly used healthy range for your height. |
| 18.5 to 24.9 | Healthy Weight | Your BMI is within the commonly used healthy adult range. |
| 25.0 to 29.9 | Overweight | Your BMI is above the healthy range and may be linked with higher health risk. |
| 30.0 to 34.9 | Obesity Class 1 | Your BMI is in the first obesity category. |
| 35.0 to 39.9 | Obesity Class 2 | Your BMI is in the second obesity category. |
| 40.0 or higher | Obesity Class 3 | This category is sometimes called severe obesity. |
Why BMI Can Be Helpful
BMI is quick, simple, and useful for general weight screening. It can help adults understand whether their weight may be above or below a commonly used healthy range. Many healthcare professionals use BMI alongside other information such as waist size, blood pressure, blood sugar, cholesterol, medical history, diet, activity level, and physical examination.
Limitations of BMI
BMI is not perfect. It does not directly measure body fat. A muscular person may have a high BMI without having excess body fat. Older adults may have different body composition than younger adults. Pregnancy, fluid retention, certain medical conditions, and athletic body types can also make BMI less accurate.
Important Health Disclaimer
This BMI calculator is for educational use only. It is not a substitute for medical advice, diagnosis, or treatment. If you have concerns about your weight, nutrition, pregnancy, chronic disease, eating habits, or sudden weight change, consult a qualified doctor, pharmacist, dietitian, or healthcare provider.
BMI Calculator FAQs
What is a BMI calculator?
A BMI calculator estimates your Body Mass Index using your height and weight. It helps place your BMI into a general adult category such as underweight, healthy weight, overweight, or obesity.
What is a healthy BMI?
For most adults aged 20 and older, a BMI from 18.5 to 24.9 is commonly considered within the healthy weight range.
Can children use this BMI calculator?
This tool is designed for adults. Children and teenagers need age- and sex-specific BMI percentiles, so they should use a child BMI calculator or consult a healthcare provider.
Is BMI the same as body fat percentage?
No. BMI is based only on height and weight. It does not directly measure body fat percentage, muscle, bone mass, or fat distribution.
What should I do if my BMI is high?
A high BMI may suggest increased health risk, but BMI alone cannot diagnose your health. Consider speaking with a healthcare provider for a complete assessment and safe weight management advice.