BMI Calculator
BMI Calculator – Check Your Body Mass Index & Weight Category
Use this BMI calculator to quickly find your Body Mass Index (BMI) and understand whether your weight falls into underweight, normal, overweight, or obese range. Simply enter your height and weight, and the tool will instantly calculate your BMI along with your healthy weight range.
You can switch between Metric units (kg/cm) and US units (lbs/feet) for convenience. The calculator also helps you estimate whether you should gain, maintain, or lose weight based on standard BMI guidelines.
What is BMI?
Body Mass Index (BMI) is a simple measurement that compares your weight to your height. It is widely used as a quick screening tool to evaluate whether a person has a healthy body weight.
BMI helps categorize weight into:
- Underweight
- Normal weight
- Overweight
- Obese
Although BMI does not directly measure body fat, it provides a useful starting point for assessing overall health and weight status.
BMI Categories for Adults
The following ranges are commonly used for adults:
| BMI Range | Weight Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25 – 29.9 | Overweight |
| 30 – 34.9 | Obese (Class I) |
| 35 – 39.9 | Obese (Class II) |
| 40 and above | Severe obesity |
A BMI between 18.5 and 24.9 is generally considered the healthy range.
Health Risks of Being Overweight
Having a BMI above the normal range may increase the risk of:
- High blood pressure
- Type 2 diabetes
- Heart disease
- Stroke
- Joint problems
- Sleep apnea
- Fatty liver disease
- Certain cancers
- Reduced mobility
- Lower overall fitness
Maintaining a healthy BMI can help reduce these risks and improve overall well-being.
Health Risks of Being Underweight
Being underweight can also lead to health concerns such as:
- Nutritional deficiencies
- Weak immune system
- Fatigue and low energy
- Bone loss and fractures
- Hormonal imbalance
- Fertility issues
- Slower growth (in teens)
- Increased recovery time after illness
A balanced diet and healthy lifestyle can help improve weight safely.
BMI Formula
BMI is calculated using height and weight.
Metric formula:
BMI = weight (kg) ÷ height² (m)
US formula:
BMI = 703 × weight (lbs) ÷ height² (inches)
The calculator above automatically performs this calculation.
Limitations of BMI
BMI is a helpful guideline, but it has some limitations:
- It does not measure body fat directly
- Muscular individuals may show higher BMI
- Age and gender are not considered
- Athletes may appear overweight
- Body composition varies between individuals
For best results, BMI should be used along with waist measurement, lifestyle, and medical advice.
What is a Healthy BMI?
A healthy BMI range for most adults is:
18.5 to 24.9
Within this range:
- Risk of disease is lower
- Energy levels are better
- Mobility improves
- Overall health is balanced
Why Use This BMI Calculator?
This free BMI calculator helps you:
✔ Calculate BMI instantly
✔ Check weight category
✔ Know if you’re overweight
✔ See healthy weight range
✔ Switch between metric and US units
✔ Understand health risk level
✔ Track fitness goals
Frequently Asked Questions
Is BMI accurate?
BMI is a general guideline. It works well for most people but does not measure body fat directly.
What BMI is overweight?
A BMI of 25 or higher is considered overweight.
What BMI is normal?
A BMI between 18.5 and 24.9 is considered normal.
What BMI is obese?
A BMI of 30 or above falls into the obese category.