My BMI

What is my BMI? Your Body Mass Index (BMI) is a simple number calculated from your height and weight. It is widely used to screen for weight categories that may signal potential health risks. Use the calculator to find your personal BMI instantly.

The calculator above computes your BMI using either metric (kilograms and meters) or imperial (pounds and inches) units. No matter which you choose, the interpretation of the resulting number remains the same.

What Is BMI?

BMI, or body mass index, is a statistical measure that compares your weight to your height. It was devised in the 19th century by Belgian mathematician Adolphe Quetelet and remains one of the most convenient screening tools for weight-related health issues.

Because BMI is quick, free, and reasonably correlated with body fatness in the general population, health organizations worldwide use it to classify adults into weight categories.

How to Calculate Your BMI Manually

If you prefer to calculate BMI without a tool, the formulas are straightforward.

Metric formula:
BMI = weight (kg) / [height (m)]²

Divide your weight in kilograms by your height in meters squared.

Example: A person weighing 68 kg with a height of 1.65 m has a BMI of
68 ÷ (1.65 × 1.65) = 24.98

Imperial formula:
BMI = (weight (lb) / [height (in)]²) × 703

Multiply your weight in pounds by 703, then divide by your height in inches squared.

Example: A 150‑lb individual who is 5′5″ (65 inches) tall has a BMI of
(150 × 703) ÷ (65 × 65) = 105,450 ÷ 4,225 = 24.96

Both formulas give the same value when using equivalent units. The calculator does this math automatically.

BMI Categories and What They Mean

The World Health Organization (WHO) recommends the following adult BMI ranges. These apply to men and women aged 20 years and older.

A BMI in the healthy range is associated with the lowest risk of weight‑related illnesses. However, your BMI is just one piece of your overall health picture.

Is BMI Accurate? Limitations of BMI

BMI does not directly measure body fat. It relies only on total body mass, which means it cannot distinguish between fat, muscle, and bone. This creates well‑known limitations.

• Athletes and muscular individuals may fall into the overweight or obese categories even though they have low body fat.
• Older adults often lose muscle mass; their BMI may read as normal while their body fat percentage is high.
• Ethnic differences exist. For example, people of Asian descent may face higher health risks at a lower BMI compared to other populations.
• Bone density and frame size are not accounted for.

For these reasons, health professionals often pair BMI with other measures like waist circumference, blood pressure, and lab tests.

Tips for a Healthy Weight

Whether your BMI is outside the normal range or you simply want to maintain a healthy weight, a few evidence‑based steps can make a difference.

• Monitor portions: Even healthy foods add up. Keep an eye on serving sizes.
• Move daily: Aim for at least 150 minutes of moderate activity each week–brisk walking counts.
• Prioritise whole foods: Vegetables, fruits, lean proteins, and whole grains keep you full and nourished.
• Watch liquid calories: Sugary drinks and alcohol can contribute significant calories without satisfying hunger.
• Sleep 7–9 hours: Short sleep disrupts hunger hormones and can lead to weight gain.
• Manage stress: Chronic stress raises cortisol, often triggering cravings and fat storage around the abdomen.

Remember, sustainable change comes from habits you can stick with, not extreme diets.

This calculator provides estimates for educational purposes. It does not replace professional medical advice, diagnosis, or treatment.