The BMI Calculator works out your Body Mass Index from your height and weight. Enter your measurements in metric (cm and kg) or imperial (feet, inches, and pounds) units and it instantly shows your BMI, which weight category you fall into, and the healthy weight range for your height.
BMI is a widely used screening number that estimates whether your weight is in a healthy range relative to your height. This calculator also offers Asian / Indian BMI ranges, because health risks for people of South Asian descent can begin at a lower BMI than the standard WHO thresholds. Everything is calculated in your browser and nothing is stored.
How to calculate your BMI
- Choose your units — metric (cm, kg) or imperial (ft, in, lb).
- Enter your height and weight.
- Pick the BMI standard: WHO (standard) or Asian / Indian for South Asian body types.
- Read your BMI value, category, and healthy weight range instantly.
How BMI is calculated
BMI is your weight in kilograms divided by the square of your height in metres (kg/m²). For example, a person who is 1.70 m tall and weighs 65 kg has a BMI of 65 ÷ (1.70 × 1.70) ≈ 22.5, which is in the normal range.
This calculator does the conversion for you whether you enter metric or imperial measurements, so you do not need to convert units by hand.
BMI categories
- Underweight: below 18.5
- Normal weight: 18.5 – 24.9 (WHO) or 18.5 – 22.9 (Asian / Indian)
- Overweight: 25 – 29.9 (WHO) or 23 – 24.9 (Asian / Indian)
- Obese: 30 and above (WHO) or 25 and above (Asian / Indian)
Limitations of BMI
BMI is a quick screening tool, not a diagnosis. It does not distinguish between muscle and fat, so very muscular people may have a high BMI while being healthy, and it may underestimate body fat in older adults. It is also not designed for children, pregnant people, or athletes.
Use BMI as a general guide and speak to a doctor or dietitian for a full picture of your health.
Frequently Asked Questions
What is a healthy BMI?
For most adults a BMI between 18.5 and 24.9 is considered healthy under WHO guidelines. For people of South Asian descent, the healthy range is often set slightly lower, at 18.5 to 22.9.
Why is there a separate Asian / Indian BMI range?
Research shows that people of South Asian descent tend to develop health risks such as diabetes and heart disease at a lower BMI than other populations. WHO and Indian health bodies therefore recommend lower overweight (23) and obese (25) cutoffs for this group.
How do I calculate BMI from height and weight?
Divide your weight in kilograms by your height in metres squared (kg/m²). This calculator does it automatically for both metric and imperial measurements.
Is BMI accurate for everyone?
No. BMI does not account for muscle mass, body composition, age, or sex, so it can be misleading for athletes, older adults, and others. It is a screening tool, not a medical diagnosis — consult a healthcare professional for personalised advice.
What is my ideal weight for my height?
The calculator shows a healthy weight range for your height, based on the normal BMI band. Any weight within that range corresponds to a healthy BMI for your height.