What is BMI and how do you calculate it?

BMI (Body Mass Index) is a measure that compares your weight to your height. How to calculate: weight (kg) divided by height squared (meters). Example: weight 70 kg, height 1.75 m → BMI = 70 ÷ (1.75)² = 22.86. Your result determines your weight category: underweight, normal, overweight, or obese.

Is BMI accurate for athletes and bodybuilders?

Not always. BMI doesn't distinguish between muscle and fat. Athletes with high muscle mass often fall into the 'overweight' category despite being healthy. Conversely, older adults with low muscle mass might appear 'normal' while undernourished. BMI is a screening tool, not a diagnosis.

What's the difference between normal, overweight, and obese BMI?

BMI categories: Underweight (below 18.5), Normal (18.5–24.9), Overweight (25–29.9), and Obese (30 and above). These categories are based on WHO standards and serve as initial health risk indicators. The higher your BMI above normal, the greater the risk of diseases like diabetes and heart disease.

How do I lower my BMI if I'm overweight?

Lower BMI with a calorie deficit (eat 300–500 kcal below your daily needs), combine weight training and cardio, increase protein and fiber, reduce sugar and processed foods. Target 0.5–1 kg loss per week for healthy, sustainable results.

Can BMI be used for children and teenagers?

BMI for children and teens uses percentiles based on age and gender, not absolute numbers like adults. Consult a pediatrician for proper interpretation.

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Weight (kg)

Height (cm)

BMI Scale 10 — 40

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Underweight Normal Overweight Obese

Your BMI

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Your Ideal Weight Range:

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What Is BMI?

BMI (Body Mass Index) is a quick way to measure if your weight is ideal for your height. BMI is used by doctors, gym trainers, and fitness apps like G-Trackt for an initial body composition estimate — without expensive equipment.

The calculation is simple: weight (kg) divided by height squared (meters). The result falls into one of four categories: Underweight, Normal, Overweight, or Obese. Each gives a rough picture of potential health risks.

But remember — BMI is an estimate, not a diagnosis. Athletes and bodybuilders with high muscle mass might fall into "Overweight" despite being healthy. Similarly, older adults losing muscle mass might appear "Normal" while undernourished. Use BMI as a starting point, and consult healthcare professionals for more accurate results.

How to Calculate BMI

Don't worry, the formula is simple. You can use the calculator above, or calculate manually with this formula:

BMI Formula

BMI = Berat (kg) ÷ (Tinggi (m))²

Example: 70 kg ÷ (1.75 m)² = 22.86 (Normal)

Convert height cm → meters

Divide height (cm) by 100

Square height (m)

Height (m) × Height (m)

Divide weight by result

Weight (kg) ÷ Squared result

BMI Categories

These are the international WHO standards used by G-Trackt:

<18.5

Underweight

Your weight is below the ideal range. You may need to increase nutritional intake or consult a dietitian. Could be a sign of fast metabolism or insufficient food intake.

18.5–24.9

Normal

Your weight is ideal — keep it up! Maintain healthy eating habits and regular exercise. Track your progress in G-Trackt to stay consistent and maximize results.

25–29.9

Overweight

Your weight is in the overweight range. Time to get moving — a combination of weight training and moderate calorie deficit can help you get back to the normal range.

≥30

Obese

BMI 30+ indicates obesity that needs attention. Risk of heart disease, diabetes, and joint issues is higher. Professional consultation and a structured fitness program are strongly recommended.

* Categories based on WHO standards. Athletes and bodybuilders may have different results due to high muscle mass.

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