BMI Calculator
Calculate your Body Mass Index (BMI) instantly with metric or imperial units. Free, private, and easy to use.
Choose metric (kg/cm) or imperial (lbs/ft-in).
Your body mass index and health category.
BMI
22.9
Category
Normal
You have a healthy weight. Keep up the good work!
Healthy Weight Range
56.7 kg — 76.3 kg
Free Online BMI Calculator — Body Mass Index with Health Categories
Calculate your Body Mass Index (BMI) instantly using metric or imperial units. This free BMI calculator shows your health category, healthy weight range, and personalized feedback.
What Is BMI?
Body Mass Index (BMI) is a numerical value derived from your weight and height. It provides a simple screening metric to categorize individuals into weight categories: underweight, normal weight, overweight, and obese. While BMI does not measure body fat directly, it is a useful indicator of potential health risks related to weight.
The BMI formula is:
- Metric: BMI = weight (kg) / height (m)²
- Imperial: BMI = (weight (lbs) / height (in)²) × 703
How to Use This BMI Calculator
- Choose your unit system — Select Metric (kg/cm) or Imperial (lbs/ft-in).
- Enter your weight — Type your weight in kilograms or pounds.
- Enter your height — Type your height in centimeters, or in feet and inches.
- View your result — Your BMI, health category, and healthy weight range appear instantly.
- Copy your result — Use the copy button to save your BMI information.
BMI Categories
| Category | BMI Range | Description |
|---|---|---|
| Underweight | Below 18.5 | May indicate nutritional deficiency or other health issues |
| Normal | 18.5 – 24.9 | Generally associated with the lowest health risks |
| Overweight | 25.0 – 29.9 | May increase risk of cardiovascular disease and diabetes |
| Obese | 30.0 and above | Significantly increased risk of various health conditions |
Key Features
| Feature | Benefit |
|---|---|
| Metric & Imperial units | Switch between kg/cm and lbs/ft-in with one click |
| Instant calculation | Results update in real time as you type |
| Health category indicator | Color-coded feedback for underweight, normal, overweight, and obese |
| BMI scale visualization | Visual bar showing where your BMI falls on the spectrum |
| Healthy weight range | Shows the ideal weight range for your height |
| Copy results | Share or save your BMI information with one click |
Real-World Use Cases
Personal Health Tracking
Monitor your BMI over time to track progress toward a healthy weight. Use this calculator monthly to see trends.
Fitness Planning
Before starting a new diet or exercise program, knowing your BMI helps you set realistic goals and choose the right plan.
Medical Consultation
Use your BMI value as a starting point for conversations with your healthcare provider about weight management.
Insurance & Health Assessments
Many health and life insurance providers use BMI as one of their assessment metrics. Know your number before applying.
Tips for Accurate BMI Measurement
- Measure your height in the morning — You are slightly taller in the morning due to spinal decompression during sleep.
- Weigh yourself consistently — Use the same scale, at the same time of day, wearing similar clothing.
- Don't rely on BMI alone — BMI does not distinguish between muscle and fat. Athletes may have a high BMI due to muscle mass.
- Consider body composition — For a complete picture, combine BMI with waist circumference and body fat percentage measurements.
- Account for age and sex — BMI thresholds may vary slightly for older adults and different populations.
Limitations of BMI
BMI is a screening tool, not a diagnostic instrument. It does not account for:
- Muscle mass — Athletes and bodybuilders may be classified as overweight despite having low body fat.
- Bone density — People with larger bone structures may have a higher BMI.
- Fat distribution — Where fat is stored (abdominal vs. hips) matters for health risk.
- Age and gender — Older adults naturally carry more fat, and women tend to have a higher body fat percentage at the same BMI.
Always consult a healthcare professional for a comprehensive health assessment.
Frequently Asked Questions
What is a healthy BMI for adults?
For most adults, a BMI between 18.5 and 24.9 is considered healthy. However, optimal BMI can vary based on age, sex, and individual health factors.
Is BMI accurate for athletes?
BMI may overestimate body fat in athletes and individuals with high muscle mass. A muscular person could be classified as overweight despite having low body fat. In these cases, body fat percentage or waist-to-hip ratio may be more useful metrics.
Does BMI apply to children?
BMI is calculated differently for children and teens (ages 2–19), using age- and sex-specific percentiles. This calculator is designed for adults only.
How often should I check my BMI?
Checking your BMI once a month is sufficient for tracking trends. Daily weight fluctuations are normal and do not reflect meaningful changes in body composition.
Can BMI predict health problems?
BMI is correlated with increased risk for conditions like type 2 diabetes, heart disease, and certain cancers. However, it is not a standalone predictor — lifestyle, family history, and other factors also play significant roles.
Does this tool store my health data?
No. All calculations happen entirely in your browser. No weight, height, or BMI data is sent to any server or stored anywhere.