BMI Calculator
Calculate your body mass index and understand what it means for your health
Calculate Your BMI
target Weight Goals Calculator
See how much weight you'd need to lose or gain to reach different BMI categories.
Calculate your BMI first to see weight goals
analytics Advanced Metrics
BMI Prime: Values below 1.0 indicate underweight, 1.0-1.25 is normal range.
Ponderal Index: Alternative to BMI that accounts for height cubed. Normal range: 11-15.
BAI: Estimates body fat percentage from hip circumference and height (approximated here).
history BMI History Tracker
Track your BMI over time. Data is saved in your browser.
No BMI history saved yet
table_chart BMI Categories Reference
| Category | BMI Range | Health Risk | Description |
|---|---|---|---|
| Underweight | < 18.5 | Increased | May indicate malnutrition, eating disorders, or other health issues |
| Normal | 18.5 - 24.9 | Low | Healthy weight range with lowest risk for weight-related health problems |
| Overweight | 25 - 29.9 | Moderate | Increased risk for cardiovascular disease and type 2 diabetes |
| Obese Class I | 30 - 34.9 | High | Significantly elevated risk for multiple obesity-related conditions |
| Obese Class II | 35 - 39.9 | Very High | Severe obesity with substantial health risks |
| Obese Class III | ≥ 40 | Extremely High | Morbid obesity requiring medical intervention |
Free BMI Calculator - Calculate Your Body Mass Index
Use our free online BMI calculator to quickly determine your body mass index and understand what it means for your health. BMI is a simple screening tool that helps assess whether you're at a healthy weight for your height.
What is BMI?
Body Mass Index (BMI) is a numerical value calculated from your weight and height. It provides a simple way to categorize people into weight status categories (underweight, normal weight, overweight, and obese) that may lead to health problems.
How is BMI Calculated?
The BMI formula divides your weight by your height squared:
Imperial: BMI = 703 × weight (lb) ÷ height² (in²)
BMI Calculator Features
- Dual Unit Support — Switch between metric (kg/cm) and imperial (lb/ft) systems
- Visual BMI Scale — See exactly where you fall on the BMI spectrum
- Healthy Weight Range — Discover your ideal weight range for a healthy BMI
- Weight Goals — See how much to lose or gain to reach different BMI categories
- Advanced Metrics — BMI Prime, Ponderal Index, and Body Adiposity Index
- History Tracking — Save and track your BMI over time (stored locally)
BMI Limitations
While BMI is a useful screening tool, it has several limitations:
- Doesn't measure body fat directly — Athletes with high muscle mass may have a high BMI but low body fat
- Doesn't account for fat distribution — Belly fat is more dangerous than fat stored elsewhere
- Same scale for all adults — Doesn't adjust for age, gender, or ethnicity differences
- Not suitable for everyone — Pregnant women, children, and the elderly need different assessments
When to See a Doctor
Consider consulting a healthcare provider if:
- Your BMI falls outside the normal range (below 18.5 or above 25)
- You're concerned about your weight or eating habits
- You have other risk factors for chronic diseases
- You want personalized advice on weight management
Healthy Weight Tips
- Balanced diet — Focus on whole foods, fruits, vegetables, lean proteins, and whole grains
- Regular exercise — Aim for at least 150 minutes of moderate activity per week
- Stay hydrated — Drink plenty of water throughout the day
- Adequate sleep — Get 7-9 hours of quality sleep each night
- Stress management — Practice relaxation techniques to avoid stress-related eating
Privacy
All calculations are performed entirely in your browser. Your health data is never sent to any server. BMI history is stored only in your browser's local storage.