BMI Calculator
Enter your weight and height to calculate your Body Mass Index (BMI) and determine your health category based on standard BMI ranges.
Free Online BMI Calculator – Metric & US Units (kg/cm or lbs/ft+in)
Use this free Body Mass Index (BMI) calculator to determine your health status based on your weight and height. It supports both metric units (kg, cm) and US units (lbs, feet, inches), making it convenient for users from all over the world. Our BMI tool also considers your age and gender to give contextually accurate results, especially useful for children, teens, and seniors.
What Is BMI?
BMI (Body Mass Index) is a simple, widely used tool for determining whether a person’s weight is appropriate for their height. It provides a numerical value that classifies individuals into categories such as underweight, normal, overweight, or obese. Although BMI doesn't directly measure body fat, it’s a useful general health indicator.
How to Calculate BMI
Metric Units (kg/cm):
BMI = weight (kg) / [height (m)]²
US Units (lbs/feet+inches):
BMI = (weight in lbs / [height in inches]²) × 703
Our calculator automatically performs these conversions when you select the unit type.
BMI Classification for Adults (Age 20+)
For individuals 20 years and older, the following BMI chart is generally used:
| BMI Range | Category | Health Advice |
|---|---|---|
| Less than 18.5 | Underweight | Consider gaining weight for better energy and immunity. |
| 18.5 – 24.9 | Normal weight | Maintain your weight with balanced nutrition and regular exercise. |
| 25.0 – 29.9 | Overweight | Incorporate more activity and reduce high-calorie foods. |
| 30.0 and above | Obese | Consider medical guidance for long-term health improvement. |
BMI for Children and Teenagers (2–19 years)
For people under 20, BMI is interpreted differently. Age and gender-specific percentile charts are used to determine weight category because children and teens are still growing. A BMI percentile tells you how your BMI compares to others of the same age and gender.
- Less than 5th percentile: Underweight
- 5th to less than 85th: Healthy weight
- 85th to less than 95th: Overweight
- 95th and above: Obese
Note: For accurate results in children and teens, use the CDC BMI-for-age growth charts.
Why BMI Matters
While BMI doesn't measure body fat directly, it’s a good general indicator of whether your body weight is in a healthy range. A high or low BMI may be a risk factor for health conditions like:
- ✅ Type 2 diabetes
- ✅ High blood pressure
- ✅ Cardiovascular disease
- ✅ Osteoporosis (if underweight)
- ✅ Fatty liver disease
Custom Tips Based on Age, Gender, and BMI
Our BMI tool doesn't just show a number — it gives personalized health tips based on your age group and gender. This helps make your result more relevant whether you’re a teen, adult, or senior.
FAQs – Body Mass Index
What is a healthy BMI for men and women?
The standard healthy range (18.5–24.9) applies to both men and women. However, women tend to naturally have a higher body fat percentage than men.
Should seniors use BMI?
Yes, but cautiously. In older adults, muscle loss can distort BMI, so it may not reflect true body fat or health risk.
What is the best unit to use: metric or US?
Use whatever you’re comfortable with! This tool converts both. Metric is more globally used; US units are popular in North America.
Is BMI accurate?
BMI is a quick screening tool but doesn’t measure body fat percentage or muscle mass. Athletes may have high BMI due to muscle, not fat.
Try It Now
Use our BMI calculator above — it’s fast, free, and works on any device. Simply choose your unit (kg/cm or lbs/ft+in), enter your details, and find out your BMI and health category instantly.
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