What is Body Mass Index (BMI)?

Body Mass Index (BMI) is a numerical measure of a person's weight relative to their height. Calculated as weight (kg) divided by height squared (m²), it is used worldwide as a screening tool to classify weight categories — underweight, normal weight, overweight, and obese. While BMI does not directly measure body fat, it is a practical and widely used first-line health assessment.

How is BMI calculated?

BMI is calculated using the formula: BMI = weight (kg) ÷ height (m)². For example, a person who is 170 cm (1.70 m) tall and weighs 70 kg has a BMI of 70 ÷ (1.70 × 1.70) = 24.2. In imperial units, the formula is: BMI = [weight (lbs) ÷ height (in)²] × 703.

What is a normal BMI for Indians and South Asians?

For Indians and South Asians, the WHO Asian-Pacific guidelines recommend a Normal BMI range of 18.5 to 22.9. Overweight begins at BMI 23 and Obesity at BMI 27.5 — both significantly lower than the Western thresholds of 25 and 30. This is because South Asians carry more visceral (abdominal) fat at lower BMI levels, which raises metabolic and cardiovascular risk earlier.

Why do Indian BMI thresholds differ from Western standards?

Research consistently shows that South Asians develop type 2 diabetes, hypertension, and cardiovascular disease at lower BMI values than Western populations. This is due to genetic differences in body fat distribution — South Asians store more fat centrally (around the abdomen and organs) at the same overall BMI. The WHO Expert Consultation in 2004 endorsed lower action thresholds of 23 (overweight) and 27.5 (obese) for Asian populations.

Is BMI 24 considered overweight for Indians?

Yes. Using WHO Asian-Pacific guidelines, a BMI of 24.0 falls in the Overweight category for South Asians (range: 23.0–27.4). Under Western standards, BMI 24.0 would be considered Normal. This is an important distinction — at BMI 24, an Indian person has an elevated risk of developing type 2 diabetes and should consider lifestyle modifications.

What is the healthy weight for someone 170 cm tall?

For a person 170 cm (1.70 m) tall, the healthy weight range using Asian-Pacific guidelines (BMI 18.5–22.9) is approximately 53.5 kg to 66.1 kg (117.9 lbs to 145.8 lbs). Using Western guidelines (BMI 18.5–24.9), the range would be slightly wider at 53.5 kg to 71.9 kg. The Asian-Pacific range is recommended for Indians and South Asians.

What is the healthy weight for someone 180 cm tall?

For a person 180 cm (1.80 m) tall, the healthy weight range using Asian-Pacific guidelines (BMI 18.5–22.9) is approximately 59.9 kg to 74.1 kg (132.1 lbs to 163.5 lbs). A weight of 90 kg at this height gives a BMI of 27.8, which falls in the Obese category per Asian-Pacific standards and Overweight under Western standards.

Is BMI accurate for everyone?

BMI has known limitations. It does not differentiate between muscle mass and body fat — athletes may score as overweight despite very low body fat. It also does not account for fat distribution, bone density, age, or gender. For a more complete picture, combine BMI with body fat percentage measurement and waist circumference. For men, a waist over 90 cm (35 in) and for women over 80 cm (31.5 in) indicates elevated risk independent of BMI.

What is the difference between BMI and body fat percentage?

BMI is a simple weight-to-height ratio and does not directly measure body fat. Body fat percentage tells you what proportion of your total body weight is fat tissue. Two people can have the same BMI but very different body compositions — an athlete with high muscle mass and a sedentary person may both have BMI 26, but the athlete has far less body fat. Body fat percentage is a more accurate measure of health and fitness.

Does BMI differ for men and women?

The BMI formula and thresholds are the same for men and women. However, women naturally carry more body fat than men at the same BMI due to hormonal and physiological differences. At BMI 22, women typically have about 28–32% body fat, while men have about 18–22%. This means BMI may slightly underestimate health risk in women with low muscle mass and overestimate it in muscular men.

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BMI Calculator - Calculate Body Mass Index & Healthy Weight

Secure & Private

Notice

All calculations are performed locally on your device. No personal health data is sent to any server.

Uses WHO Asian-Pacific BMI Cutoffs (23 / 27.5)

Details

This calculator applies the WHO Asian-Pacific thresholds recommended for South Asian populations. Overweight starts at BMI 23, Obese at BMI 27.5 — lower than Western standards.

Physical Parameters

Height (cm)

Weight (kg)

Age (years) Affects recommendations for children and elderly.

Biological Gender

Used for body composition context.

Example Presets

Load representative profiles to see BMI categories in action:

BMI Result

Awaiting Parameters

Enter your weight, height, and age above to compute your Body Mass Index.

BMI SCORE 22.4

Normal Weight

Your Body Mass Index indicates a healthy weight per Asian-Pacific standards.

WHO Asian-Pacific BMI Spectrum

22.4

< 18.5 18.5–22.9 23–27.4 ≥ 27.5

Healthy Weight Range (BMI 18.5–22.9)

For your height of 170 cm: 53.5 kg – 66.1 kg

Equivalent to: 117.9 lbs – 145.8 lbs

Ideal Weight Range

Target for Normal BMI (18.5–22.9): —

Weight to Reach Normal BMI

—

Next Health Goal

—

Personalised Recommendation

Maintain your fitness routine and prioritise a balanced diet rich in whole foods, vegetables, and lean proteins.

Related Health Calculators

Body Fat Calculator BMR Calculator Calorie Calculator Ideal Weight Calculator TDEE Calculator Waist-Hip Ratio

BMI Categories

WHO Asian-Pacific cutoffs are used in this calculator, specifically recommended for Indian and South Asian populations. These differ from Western standards where overweight begins at 25 and obesity at 30.

Underweight

< 18.5

Low body fat or muscle mass. Risk of nutrient deficiencies, osteoporosis, and weak immune system.

Normal Weight

18.5 – 22.9

Optimal range for South Asians. Lowest risk of weight-related chronic disease.

Overweight

23.0 – 27.4

Increased risk of type 2 diabetes and cardiovascular disease in South Asians at this range.

Obese

≥ 27.5

High risk of diabetes, hypertension, heart disease, and metabolic syndrome. Medical advice recommended.

Western vs. Asian-Pacific BMI Thresholds

Category	WHO Standard (Western)	WHO Asian-Pacific
Underweight	< 18.5	< 18.5
Normal	18.5 – 24.9	18.5 – 22.9 ✓
Overweight	25.0 – 29.9	23.0 – 27.4 ✓
Obese	≥ 30.0	≥ 27.5 ✓

BMI for Indians & South Asians

South Asians — including Indians, Pakistanis, Bangladeshis, and Sri Lankans — have a higher body fat percentage at the same BMI compared to Western populations. This means health risks appear at lower BMI values.

Why Different Thresholds?

Research shows South Asians have higher visceral (abdominal) fat at lower BMI levels. At BMI 23, an Indian person has the same cardiovascular risk as a European at BMI 25. This is due to genetic differences in fat distribution — more central fat storage for the same total body weight.

Health Risks at Lower BMI

Type 2 diabetes in South Asians often appears at BMI 22–24 — 2–4 units lower than in European populations. Hypertension and insulin resistance also develop earlier. The WHO Expert Consultation (2004) confirmed that action points for public health should be lower for Asian populations.

Healthy BMI Range for Indians

The optimal BMI range for Indians and South Asians is 18.5–22.9. A BMI of 23 or above warrants lifestyle changes. At 27.5 or above, medical consultation is strongly advised. Waist circumference is also a useful complementary measure — men: <90 cm, women: <80 cm.

Recommended by Medical Bodies

The WHO, Indian Council of Medical Research (ICMR), and the Diabetes Foundation of India all endorse lower BMI cut-offs for South Asians. The National Family Health Survey (NFHS) in India also uses these lower thresholds for population-level health screening.

BMI Limitations

BMI is a useful population-level screening tool, but it has well-known limitations for individual assessment.

Muscle Mass

Athletes and bodybuilders may have a high BMI due to muscle, not fat. A rugby player at 190 cm / 100 kg (BMI 27.7) may have very low body fat. BMI cannot distinguish fat from lean tissue.

Fat Distribution

Visceral fat (around organs) is more dangerous than subcutaneous fat. Two people at the same BMI can have very different waist sizes and health risks. Waist-to-height ratio is often a better predictor of metabolic risk.

Age & Gender

Older adults naturally lose muscle and gain fat, so BMI may underestimate risk. Women typically carry more body fat than men at the same BMI. Children require BMI-for-age percentile charts, not adult thresholds.

Better Alternatives to BMI

Body Fat %

Directly measures adipose tissue vs lean mass. More accurate for individual health assessment.

Waist-to-Hip Ratio

Measures central fat distribution. Men: <0.9 (healthy), Women: <0.8 (healthy).

Waist-to-Height Ratio

Keep waist <50% of height. Simple, no equipment needed, good predictor of metabolic risk.

BMI calculations are standard clinical approximations. Under no circumstances should results be treated as absolute medical diagnostics. Consult qualified healthcare professionals for health assessments.