How do I calculate BMI online for free?

Enter your weight and height on AMOZUnique BMI Calculator, choose metric (kg/cm) or imperial (lbs/ft), click Calculate BMI, and instantly see your BMI value, category, and healthy weight range. No signup required.

What is BMI and how is it calculated?

BMI stands for Body Mass Index. It is calculated by dividing weight in kilograms by height in meters squared: BMI = weight(kg) / height(m)^2. For imperial: BMI = 703 x weight(lbs) / height(inches)^2.

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⚖️ BMI Calculator Online Free

Calculate your Body Mass Index (BMI) instantly. Supports metric and imperial units. See your BMI category and healthy weight range. No signup required.

Weight (kg)

Height (cm)

Gender (optional)

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Your BMI--

Category--

Healthy weight range--

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BMI Calculator Online Free — Calculate Body Mass Index Instantly

Our free online BMI calculator helps you calculate your Body Mass Index instantly using metric (kg/cm) or imperial (lbs/ft) units. See your BMI value, category, visual gauge, and healthy weight range — no signup, no app download needed.

BMI Categories for Adults

Underweight: BMI below 18.5
Normal weight: BMI 18.5 – 24.9
Overweight: BMI 25 – 29.9
Obese Class 1: BMI 30 – 34.9
Obese Class 2: BMI 35 – 39.9
Obese Class 3: BMI 40 and above

BMI Formula

Metric: BMI = weight(kg) ÷ height(m)²
Imperial: BMI = 703 × weight(lbs) ÷ height(inches)²

Limitations of BMI

BMI is a useful screening tool but does not measure body fat directly. It does not account for muscle mass, bone density, age, or gender. Athletes may show high BMI due to muscle. Always consult a healthcare professional for medical advice.

Healthy BMI Range

The World Health Organization (WHO) defines a healthy BMI as 18.5 to 24.9 for adults. Maintaining a healthy BMI reduces risk of heart disease, diabetes, and other conditions.

How to Use the BMI Calculator

Select your unit system: Metric (kg/cm) or Imperial (lb/ft-in)
Enter your weight and height
Click Calculate BMI
View your BMI value and weight category instantly

Frequently Asked Questions — BMI Calculator

What is a healthy BMI range?

Healthy BMI is 18.5 to 24.9. Below 18.5 is underweight, 25-29.9 is overweight, 30+ is obese.

How is BMI calculated?

Metric: BMI = weight(kg) ÷ height(m)². Imperial: BMI = 703 × weight(lbs) ÷ height(inches)².

Is BMI accurate for everyone?

BMI is a screening tool, not a direct fat measurement. It may not be accurate for athletes, elderly, or pregnant women. Consult a doctor for medical assessment.

What BMI is considered obese?

BMI 30 or above is classified as obese. 30-34.9 is Class 1, 35-39.9 is Class 2, 40+ is Class 3 severe obesity.

Does BMI differ for men and women?

The same BMI scale applies to both men and women, but body fat percentage differs. Women naturally have higher body fat at the same BMI than men.