Body Mass Index (BMI) is the quickest way to check whether your weight is in a healthy range for your height. But the BMI categories most websites show were designed for Western populations – and research shows that Indians face health risks at a lower BMI. This guide explains how to calculate BMI in kg and cm or in feet and pounds, gives a BMI chart for adults with both the international and Asian BMI cut-offs, and shows the healthy BMI range for Indians at every height.
What Is BMI?
BMI is a simple number that relates your weight to your height. Doctors use it as a first screening tool for underweight, overweight and obesity because it is quick, free and closely linked to health risks such as type 2 diabetes, high blood pressure and heart disease across large groups of people. It is not a direct measure of body fat, so it works best alongside other checks such as waist size.
BMI Formula: How to Calculate BMI
BMI in kg and cm (metric)
BMI = Weight (kg) ÷ [Height (m)]²
Example: a person who weighs 70 kg and is 170 cm (1.70 m) tall has a BMI of 70 ÷ (1.70 × 1.70) = 70 ÷ 2.89 = 24.2.
BMI in feet and pounds (imperial)
BMI = 703 × Weight (lb) ÷ [Height (in)]²
Example: 154 lb at 5 feet 7 inches (67 inches): 703 × 154 ÷ (67 × 67) = 24.1 – the same person in different units.
That is the whole BMI formula. The same calculation is used in every BMI calculator for men and BMI calculator for women – adult BMI does not change with sex or age.
BMI Categories: WHO vs Asian-Indian
The World Health Organization's international categories are widely used, but Indian and Asian experts recommend lower cut-offs because people of South Asian origin tend to have more body fat and more abdominal fat at the same BMI.
| Category | WHO (international) | For Asian Indians |
|---|---|---|
| Underweight BMI | Below 18.5 | Below 18.5 |
| Normal BMI | 18.5 – 24.9 | 18.5 – 22.9 |
| Overweight BMI | 25.0 – 29.9 | 23.0 – 24.9 |
| Obese BMI | 30.0 and above | 25.0 and above |
By the international chart, our 70 kg, 170 cm example (BMI 24.2) is "normal". By the BMI for Indians guidelines – based on the Indian consensus guidelines on obesity – the same person is "overweight" and should watch their waist size, blood sugar and blood pressure. This is why a BMI calculator India users can trust should show both.
BMI Chart: Healthy Weight for Height
This BMI chart shows the ideal weight for height range that keeps BMI in the normal band:
| Height | Healthy weight (WHO 18.5–24.9) | Healthy weight for Indians (18.5–22.9) |
|---|---|---|
| 150 cm (4′11″) | 41.6 – 56.0 kg | 41.6 – 51.5 kg |
| 155 cm (5′1″) | 44.4 – 59.8 kg | 44.4 – 55.0 kg |
| 160 cm (5′3″) | 47.4 – 63.7 kg | 47.4 – 58.6 kg |
| 165 cm (5′5″) | 50.4 – 67.8 kg | 50.4 – 62.3 kg |
| 170 cm (5′7″) | 53.5 – 72.0 kg | 53.5 – 66.2 kg |
| 175 cm (5′9″) | 56.7 – 76.3 kg | 56.7 – 70.1 kg |
| 180 cm (5′11″) | 59.9 – 80.7 kg | 59.9 – 74.2 kg |
| 185 cm (6′1″) | 63.3 – 85.2 kg | 63.3 – 78.4 kg |
So what is a healthy weight? For a 165 cm adult of Indian origin, roughly 50–62 kg. For a more personal target, try our ideal weight calculator.
Waist Circumference and Waist-to-Height Ratio
Where you carry fat matters as much as how much you weigh. Fat around the belly (visceral fat) is linked to diabetes and heart disease even when BMI is normal – a pattern often called the "thin-fat Indian" phenotype. Two quick checks help:
- Waist circumference: measure around your waist at the level of the navel. For Indian adults, a waist above 90 cm (35.4 in) in men or 80 cm (31.5 in) in women signals higher risk.
- Waist to height ratio: divide your waist by your height in the same units. Keep it below 0.5 – in other words, your waist should be less than half your height.
UK users can check both BMI in stones and pounds and waist-to-height ratio with our BMI calculator UK.
BMI and Health Risks
A BMI outside the healthy range is linked to several health problems:
- High BMI: type 2 diabetes, high blood pressure, high cholesterol, fatty liver, heart disease, stroke, sleep apnoea, joint pain and some cancers. India has one of the world's largest populations of people with diabetes, and many develop it at a lower BMI than Western populations.
- Low BMI: weak immunity, anaemia, bone loss (osteoporosis), fertility problems and slow recovery from illness.
If your BMI is in the overweight or obese range for Indians, a yearly check of fasting blood sugar (or HbA1c), blood pressure and cholesterol is a sensible precaution – even if you feel well.
Common BMI Myths
- "A normal BMI means I am healthy." Not always – belly fat, smoking, inactivity and family history matter too.
- "BMI is different for men and women." For adults the formula and categories are the same; only children's BMI depends on sex and age.
- "I should aim for the lowest BMI possible." A BMI below 18.5 carries its own risks. Aim for the middle of the healthy range.
- "Weight alone tells the story." Two people with the same weight can have very different BMIs if their heights differ – always compare weight with height.
BMI Limitations: What BMI Cannot Tell You
- Muscle vs fat: athletes and people who lift weights may have a high BMI without excess fat.
- Older adults may lose muscle and have too much fat even with a "normal" BMI.
- Ethnicity: as shown above, South Asians face risks at lower BMIs.
- Pregnancy: BMI does not apply during pregnancy; doctors use the pre-pregnancy BMI to guide weight gain.
- Fat distribution: BMI cannot see belly fat – use waist size as well.
Understanding these BMI limitations helps you use it sensibly: as a screening number, not a diagnosis.
BMI for Children and Teenagers
Adult categories do not apply to children. BMI for children is compared with growth charts for their age and sex and given as a percentile. A child at or above the 95th percentile is considered obese, and below the 5th percentile underweight. For children under five, doctors and Anganwadi workers use the WHO Child Growth Standards – you can check these with our Poshan child growth calculator.
BMI and BMR: What Is the Difference?
BMI describes your size. BMR (basal metabolic rate) is the number of calories your body burns at complete rest to keep you alive. Your daily calorie needs are your BMR multiplied by an activity factor – that total is your TDEE. To lose weight you eat slightly fewer calories than your TDEE; to gain weight, slightly more. Work out yours with our calorie calculator or TDEE calculator.
How to Reduce BMI Safely
- Aim for slow, steady loss of about 0.5 kg a week – a daily calorie deficit of around 500 calories.
- Fill half your plate with vegetables and include protein (dal, paneer, eggs, fish, chicken, sprouts) at every meal.
- Cut down refined carbs and sugar – white rice and maida in large portions, sweets, sugary drinks and fried snacks.
- Move every day: at least 150 minutes of brisk walking or other moderate activity a week, plus strength exercises twice a week.
- Sleep 7–8 hours; poor sleep increases hunger hormones.
- Track your waist as well as your weight – losing belly fat is the biggest health win.
Even a 5%–10% weight loss improves blood sugar, blood pressure and cholesterol. Talk to your doctor before starting a diet if you have a medical condition. Knowing how to reduce BMI the healthy way is better than any crash diet.
Frequently Asked Questions
How do I calculate my BMI?
Divide your weight in kilograms by the square of your height in metres. For 70 kg and 1.70 m: 70 ÷ 2.89 = 24.2. In pounds and inches, multiply weight by 703 and divide by height squared.
What is a healthy BMI for Indians?
For Asian Indians, a BMI of 18.5 to 22.9 is considered normal, 23 to 24.9 overweight and 25 or above obese. These cut-offs are lower than the international WHO categories.
Is BMI different for men and women?
No. The adult BMI formula and categories are the same for men and women. Women naturally have a higher body fat percentage at the same BMI, which is why waist size is a useful extra check.
What is the ideal weight for 165 cm height?
For a healthy BMI, about 50.4 to 67.8 kg by international standards, or 50.4 to 62.3 kg using the lower cut-off recommended for Indians.
Is a BMI of 24 good?
By WHO standards a BMI of 24 is normal. For Asian Indians it falls in the overweight range (23 to 24.9), so it is a good idea to check your waist size and keep an eye on blood sugar and blood pressure.
What waist size is healthy for Indian adults?
Below 90 cm for men and below 80 cm for women. A waist-to-height ratio under 0.5 is another good target.
Can BMI be used for children?
Not with adult categories. Children's BMI is compared with age and sex percentiles, and children under five are assessed with the WHO growth standards.
Disclaimer: BMI is a screening tool, not a diagnosis. Weight ranges are rounded to one decimal place. This article is general health information and does not replace advice from your doctor or a registered dietitian.