BMI Calculator: Check Your Body Mass Index
Body mass index (BMI) compares your weight with your height. Enter both in metric or imperial units to see your BMI, the WHO category, the stricter Asian and Indian cut-offs, and the weight range that counts as healthy for your height.
Educational estimate only. It is not medical advice or a diagnosis. Talk to a doctor or registered dietitian before changing your diet or exercise.
More Health & Fitness calculators
View all 10You may also need
From related categoriesHow to use this calculator
- Choose metric or imperial units.
- Enter your height and weight. In imperial, enter feet and inches separately.
- Read your BMI and the scale that shows where it falls.
- Check the healthy weight range for your height to see how far you are from it.
The formula
Worked example
A person who is 170 cm tall and weighs 70 kg: height in metres is 1.70, so BMI = 70 ÷ (1.70 × 1.70) = 70 ÷ 2.89 = 24.2. That is in the WHO healthy range of 18.5 to 24.9, and the healthy weight range for 170 cm is about 53.5 to 72 kg.
Understanding your result
WHO adult categories are underweight below 18.5, healthy 18.5 to 24.9, overweight 25 to 29.9 and obese 30 or more. For Asian populations, including India, risk starts at lower values, so the Asia-Pacific cut-offs mark overweight from 23 and obese from 25. BMI does not measure body fat or show where fat sits.
When to use it
- Get a quick screening number for general health.
- Find a target weight range for your height.
- Track change over months alongside waist size and fitness.
In-depth guide
BMI categories
The World Health Organization groups adult BMI into the ranges below. These are screening bands, not a diagnosis.
| BMI | WHO category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 to 24.9 | Healthy range |
| 25.0 to 29.9 | Overweight |
| 30.0 and above | Obesity |
Studies in Asian populations have found that health risks can start at a lower BMI. Many Indian and Asia-Pacific guidelines therefore use about 23 as the start of the overweight range and 25 for obesity. Ask your doctor which cut-offs apply to you.
Healthy weight range by height
Using the BMI range of 18.5 to 24.9, the weight range for common heights is:
| Height | Healthy weight range |
|---|---|
| 150 cm | 41.6 to 56.0 kg |
| 155 cm | 44.4 to 59.8 kg |
| 160 cm | 47.4 to 63.7 kg |
| 165 cm | 50.4 to 67.8 kg |
| 170 cm | 53.5 to 72.0 kg |
| 175 cm | 56.7 to 76.3 kg |
| 180 cm | 59.9 to 80.7 kg |
What BMI cannot tell you
- It does not separate muscle from fat, so a muscular person can have a high BMI with low body fat.
- It does not show where fat is stored. Fat around the waist carries more health risk than fat elsewhere.
- It can mislead in older adults, who lose muscle, and during pregnancy.
- It is not used for children and teenagers. Growth charts for age are used instead.
Other measures worth knowing
Waist circumference, waist-to-height ratio and body fat percentage give more detail. Blood pressure, blood sugar and cholesterol tests tell you more about health than any single number. Use BMI as a starting point for a conversation with a doctor, not as a verdict.
Using the result sensibly
If your BMI is outside the healthy range, a gradual change in food, activity and sleep is safer than a crash plan. For calorie targets see the Calorie Calculator, and speak to a doctor or registered dietitian before making big changes. This page is educational and is not medical advice.
Assumptions and limits
Educational estimate, not medical advice. A doctor or registered dietitian can give guidance that fits your health. BMI is a screening tool for adults. It can mislead for athletes and muscular people, older adults, pregnancy, and anyone under 18, where growth charts are used instead.
Frequently asked questions
What is a healthy BMI?
The WHO healthy range for adults is 18.5 to 24.9. Asian and Indian guidance treats 18.5 to 22.9 as the healthy band.
Why show two sets of categories?
Health risk rises at a lower BMI in South Asian populations, so Asia-Pacific cut-offs are stricter than the WHO global ones.
Is BMI accurate for athletes?
Not always. Muscle weighs more than fat, so a muscular person can have a high BMI with low body fat.
Can I use it for children?
No. Children and teens are assessed with BMI-for-age growth charts.
Does BMI diagnose a condition?
No. It is a screening number. A doctor looks at your whole health.