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BMI Calculator

Check your Body Mass Index and find out if you are in a healthy weight range.

Weight (kg) Height (cm)

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Normal

Underweight Normal Overweight Obese

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What is BMI?

BMI stands for Body Mass Index. It is a simple numerical value calculated from your weight and height. Doctors and health professionals use BMI as a quick screening tool to categorize whether a person is underweight, at a healthy weight, overweight, or obese.

While BMI does not measure body fat directly, studies have shown that it correlates closely with more direct measures of body fat and overall health risks. Maintaining a healthy BMI can reduce your risk of heart disease, diabetes, and high blood pressure.

How to use this BMI Calculator

Choose your preferred unit: Metric (kilograms and centimeters) or Imperial (pounds and feet/inches).
Enter your current weight.
Enter your height.
Click Calculate BMI.
Your BMI score will appear along with a visual scale showing which category you fall into.

The BMI Formula

The World Health Organization (WHO) uses the following standard formulas:

Metric System

BMI = Weight (kg) ÷ [Height (m)]²

Example: If you weigh 70 kg and are 1.75 meters tall:
BMI = 70 ÷ (1.75 × 1.75) = 70 ÷ 3.0625 = 22.9

Imperial System

BMI = [Weight (lbs) ÷ [Height (inches)]²] × 703

Example: If you weigh 154 lbs and are 69 inches tall:
BMI = (154 ÷ (69 × 69)) × 703 = (154 ÷ 4761) × 703 = 22.7

BMI Categories (For Adults)

According to the WHO, BMI is categorized as follows for adults aged 20 and older:

BMI Range	Category
Below 18.5	Underweight
18.5 – 24.9	Normal Weight
25.0 – 29.9	Overweight
30.0 and Above	Obese

Note: For people of Asian descent (including Indians), the WHO suggests a lower threshold for overweight (23.0 – 24.9) and obesity (25.0+), due to a higher risk of metabolic diseases at lower BMIs.

What are the limitations of BMI?

While BMI is a useful starting point, it is not perfect. It has some significant limitations:

Does not distinguish between muscle and fat: Bodybuilders and athletes often have a high BMI because muscle weighs more than fat, but they are incredibly healthy. They might be wrongly categorized as "obese".
Age and gender differences: Older adults tend to have more body fat than younger adults with the same BMI. Women generally have more body fat than men of the same BMI.
Bone density: People with denser bones may have a higher BMI despite having low body fat.
Body shape: BMI doesn't tell you where the fat is located. Visceral fat (around the belly) is much more dangerous than subcutaneous fat (under the skin).

Tips for maintaining a healthy BMI

Eat a balanced diet: Focus on vegetables, fruits, whole grains, and lean proteins. Limit processed foods and added sugars.
Stay active: Aim for at least 150 minutes of moderate aerobic activity (like brisk walking) or 75 minutes of vigorous activity per week.
Get enough sleep: Poor sleep can disrupt hormones that regulate appetite, leading to weight gain.
Manage stress: High stress levels can increase cortisol, which is linked to belly fat.
Stay hydrated: Drink water instead of sugary drinks.

Frequently asked questions

Is BMI accurate for children and teens?

No. For children and teens (ages 2-19), BMI is calculated the same way, but it is interpreted using age- and sex-specific percentiles because their body composition changes rapidly as they grow. Use a "BMI-for-age percentile calculator" for kids.

What is a healthy BMI for Indians?

The Indian government and health experts recommend a slightly stricter scale. A healthy BMI for Indians is considered 18.5 to 22.9. A BMI of 23 to 24.9 is considered overweight, and 25 or above is considered obese.

Does a normal BMI mean I am completely healthy?

Not necessarily. BMI is just one indicator. You could have a normal BMI but have high cholesterol, high blood pressure, or low muscle mass. It is always best to consult a doctor for a complete health assessment.

Is my data stored?

No. This calculator runs 100% in your browser. We don't save your weight or height on any server.