BMI Calculator
Calculate your Body Mass Index based on height and weight
Your BMI is:
0
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About Body Mass Index (BMI)
Body Mass Index (BMI) is a simple calculation using a person's height and weight to assess their weight category. It's a screening tool that can indicate whether someone is underweight, at a healthy weight, overweight, or obese.
How to Use This BMI Calculator
- Select your preferred unit for height (cm, in, ft, or m)
- Enter your height value
- Select your preferred unit for weight (kg, lb, or st)
- Enter your weight value
- Click the calculate button
- View your BMI result and category in the results section
Why We Use BMI Calculator
- Quick health assessment: BMI provides a simple way to assess if your weight is appropriate for your height
- Health monitoring: Track changes in your BMI over time to monitor weight management progress
- Risk assessment: BMI can help identify potential health risks associated with weight
- Comparison: Compare your BMI to standard health ranges recommended by health organizations
BMI Categories and Health Risks
| Category | BMI Range | Health Implications |
|---|---|---|
| Underweight | Below 18.5 | Possible nutritional deficiency, osteoporosis |
| Normal weight | 18.5 - 24.9 | Lowest health risk, maintain this range |
| Overweight | 25 - 29.9 | Increased risk of health problems |
| Obesity Class I | 30 - 34.9 | High risk of cardiovascular disease, diabetes |
| Obesity Class II | 35 - 39.9 | Very high risk of serious health conditions |
| Obesity Class III | 40 and above | Extremely high risk, severe obesity |
Limitations of BMI
While BMI is a useful screening tool, it has some limitations:
- Muscle mass: May overestimate body fat in athletes and others with muscular builds
- Age factors: May underestimate body fat in older adults who have lost muscle mass
- Body composition: Doesn't distinguish between fat, muscle, and bone mass
- Ethnic differences: BMI thresholds may vary between different ethnic groups
- Pregnancy: Not suitable for pregnant women
BMI Formula
The standard formula for calculating BMI is:
BMI = weight(kg) / (height(m))²
For imperial measurements (pounds and inches):
BMI = 703 × weight(lb) / (height(in))²
BMI was developed in the 1830s by Belgian mathematician Adolphe Quetelet. While widely used today, it was originally called the Quetelet Index and was intended for population studies rather than individual assessment.
Are these calculators really free to use?
Yes, all our calculators are completely free to use with no hidden fees or subscriptions. We believe in providing valuable tools accessible to everyone.
How accurate are the calculations?
Our calculators use industry-standard formulas and algorithms to ensure maximum accuracy. We regularly update our calculators to reflect the latest standards and practices.
Do you store my personal data?
We take privacy seriously. All calculations happen locally in your browser, and we don't store your personal data or calculation inputs on our servers.
Can I request a new calculator?
Absolutely! We're always looking to expand our calculator collection. You can submit your request through our contact form, and we'll consider adding it to our platform.