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Body Mass Index (BMI) is a simple number calculated from your height and weight. It gives a general indication of whether your weight is in a healthy range for your height. Use this free BMI calculator to get your result instantly — along with a clear explanation of what it means.
This calculator is for educational purposes only and does not replace a medical consultation. BMI has limitations — it does not account for muscle mass, bone density, body composition, age, or ethnic differences. Always consult a qualified doctor for medical advice.
Optional — helps personalise advice
BMI Categories — WHO Classification
| BMI Range | Category | Health Risk |
|---|---|---|
| Below 16.0 | Severe Underweight | Very High |
| 16.0 – 18.4 | Underweight | Moderate |
| 18.5 – 24.9 | ✅ Normal / Healthy Weight | Low |
| 25.0 – 29.9 | Overweight | Increased |
| 30.0 – 34.9 | Obese — Class I | High |
| 35.0 – 39.9 | Obese — Class II | Very High |
| 40.0 and above | Obese — Class III | Extremely High |
What Is BMI and How Is It Calculated?
BMI stands for Body Mass Index. It is a number calculated from a person’s weight and height.
BMI was developed in the 19th century by Belgian statistician Adolphe Quetelet as a population-level screening tool. Today, it is used worldwide by healthcare professionals as an initial screening measure — though it has several important limitations.
Important Limitations of BMI
BMI is a useful starting point — but it does not tell the full story of your health. Here are the key limitations to understand:
💪 Muscle vs Fat
A muscular athlete may have a high BMI but very low body fat. A sedentary person may have a normal BMI but high body fat percentage.
🌍 Ethnic Differences
South Asians (including Indians and Bangladeshis) have a higher risk of metabolic disease at lower BMI values than the standard WHO categories suggest.
👴 Age Factor
As people age, they tend to lose muscle and gain fat even without any change in weight. BMI does not capture this shift in body composition.
🤰 Special Conditions
BMI is not suitable for pregnant women, children, very elderly patients, or people with certain medical conditions affecting body fluid or bone density.
Many Indian and South Asian medical guidelines recommend considering a BMI of 23.0 or above as “overweight” and 27.5 or above as “obese” — lower thresholds than the standard WHO categories — due to a higher susceptibility to diabetes and cardiovascular disease at lower BMI values in this population.
Frequently Asked Questions
What is a healthy BMI for Indians?
For Indian and South Asian adults, many health authorities recommend a BMI between 18.5 and 22.9 as the healthy range — with 23.0–27.4 considered overweight and 27.5 and above considered obese. These thresholds are lower than the standard WHO values because South Asians tend to develop metabolic conditions like type 2 diabetes at lower BMI levels than Western populations.
Is BMI accurate for women?
BMI uses the same formula for men and women, even though women naturally have a higher body fat percentage than men at the same BMI. This means BMI may slightly underestimate health risk in women. A waist circumference measurement (greater than 80 cm in women is considered high risk) alongside BMI gives a more complete picture.
Can I have a normal BMI but still be at health risk?
Yes. This is called “normal weight obesity” — where someone has a BMI in the healthy range but carries excess fat, particularly around the abdomen. Central obesity (belly fat) is a known risk factor for diabetes, heart disease, and metabolic syndrome, even in people with a normal BMI. Waist circumference, blood sugar, cholesterol, and blood pressure give a more complete picture of metabolic health.
What should I do if my BMI is in the overweight or obese range?
Do not panic — a BMI in the overweight or obese range is a starting point for discussion, not a diagnosis. Speak with a doctor or dietitian for a full health assessment. Doctor Visit Bangalore can help connect you with a specialist in Bangalore for weight management, metabolic health evaluation, or dietary counselling. WhatsApp us at +91 78920 28951 — free guidance.
Is this BMI calculator suitable for children?
No. This calculator is designed for adults aged 18 and above. BMI in children is interpreted differently — using age-specific and gender-specific BMI-for-age percentile charts. Do not use this tool for children or teenagers. Use our separate Paediatric BMI Calculator (coming soon) for patients under 18.
When should I see a doctor about my weight?
You should consult a doctor if your BMI is below 18.5 or above 25 and you have other risk factors such as high blood sugar, high cholesterol, high blood pressure, family history of diabetes or heart disease, or if you have unexplained weight gain or loss. Doctor Visit Bangalore can help you book a consultation with an endocrinologist, dietitian, or internal medicine specialist in Bangalore.
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Disclaimer: This BMI calculator is for educational and informational purposes only. It does not constitute medical advice and should not be used as a substitute for professional medical consultation, diagnosis, or treatment. BMI is a screening tool only — not a diagnostic measure. Results should always be discussed with a qualified healthcare professional. This page follows the Doctor Visit Bangalore Editorial Policy.