Advanced BMI Calculator (Free & Accurate Online Tool)

Use our free BMI Calculator to instantly find your Body Mass Index (BMI), discover your weight category, and check your healthy weight range based on your height and weight. Supports both metric (kg/cm) and imperial (lb/ft+in) units.

BMI Calculator (Advanced)

Your BMI (Body Mass Index) is calculated from height and weight. Adults 20+ can use standard BMI ranges below. For athletes, BMI may overestimate body fat.

Your BMI
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Healthy Weight Range
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Notes
Enter details to calculate.
BMI Categories (Adults)
CategoryBMI
Underweight< 18.5
Normal (Healthy)18.5 – 24.9
Overweight25.0 – 29.9
Obesity Class I30.0 – 34.9
Obesity Class II35.0 – 39.9
Obesity Class III≥ 40.0

What is BMI (Body Mass Index)?

  • Body Mass Index (BMI) is a widely used measurement that helps determine if your weight is healthy for your height. It is calculated using the formula:

    BMI = weight (kg) ÷ [height (m)]²

    For example:

    • A person who weighs 70 kg and is 170 cm tall has a BMI of 24.2, which falls into the normal (healthy weight) range.

Why Use Our BMI Calculator?

  • Supports metric & imperial units
  • Gives instant results with category (underweight, healthy, overweight, obese)
  • Shows your healthy weight range
  • Works on all devices
  • Free to use & no signup required

How to Interpret Your BMI

  • Underweight: May indicate malnutrition or other health issues.
  • Normal (Healthy): Ideal weight for your height, lowest health risk.
  • Overweight: Increased risk of heart disease, diabetes, and other conditions.
  • Obese: Higher risk of chronic diseases, medical supervision advised.

Limitations of BMI

While BMI is a useful screening tool, it does not directly measure body fat. For athletes or muscular individuals, BMI may overestimate fat levels. For older adults, it may underestimate fat levels.

That’s why BMI should be combined with other health assessments like waist circumference, body fat percentage, and medical checkups.

Frequently Asked Questions (FAQs)

What is a healthy BMI?

A healthy BMI is between 18.5 and 24.9, according to the World Health Organization.

Is BMI accurate?

BMI is a quick estimate of healthy weight. However, it doesn’t consider muscle mass, bone density, or fat distribution.

What BMI is overweight?

A BMI of 25 or above is considered overweight.

Can BMI be used for children?

No, children and teenagers require age- and sex-specific growth charts to measure BMI correctly.

How often should I check my BMI?

Once every few months is enough, unless you’re actively tracking weight changes.

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Important Note

This BMI Calculator is provided for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Results may vary depending on individual factors such as age, sex, muscle mass, and overall health.
Always seek the guidance of your doctor or a qualified healthcare provider before making any decisions regarding your health, diet, or exercise routine.