Find your BMI, what it means, and the healthy weight range for your height – metric or imperial.
What is the BMI Calculator?
Body Mass Index (BMI) is a quick way to check if your weight is in a healthy range for your height. This BMI calculator works in metric (kg and cm) or imperial (pounds, feet and inches) units, shows your BMI category on a colour scale and tells you the healthy weight range for your height.
Because people of South Asian and East Asian origin can have higher health risks at a lower BMI, you can also switch to the Asian BMI chart recommended by the WHO for Asian populations.
How to use the BMI Calculator
- Choose metric or imperial units.
- Enter your weight and height.
- Read your BMI, category and healthy weight range.
BMI formula
BMI = weight (kg) ÷ height (m)². For example, 70 kg and 1.70 m gives 70 ÷ (1.70 × 1.70) = 24.2, which is in the normal range. In imperial units: BMI = 703 × weight (lb) ÷ height (in)².
BMI categories
| BMI | WHO category | Asian chart |
|---|---|---|
| Below 18.5 | Underweight | Underweight |
| 18.5 – 22.9 | Normal | Normal |
| 23 – 24.9 | Normal | Overweight (at risk) |
| 25 – 29.9 | Overweight | Obese class I |
| 30 and above | Obese | Obese class II |
Limitations of BMI
BMI does not tell the difference between muscle and fat, so athletes may show a high BMI while being very healthy. It is also not designed for children, pregnant women or the elderly. Use it together with waist size (try our Waist-to-Hip Ratio calculator) and talk to a doctor for a full picture.
Frequently asked questions
What is a healthy BMI?
Between 18.5 and 24.9 for most adults, or 18.5 to 22.9 using the Asian chart.
Is BMI accurate?
It is a useful screening number for most adults but does not measure body fat directly.
Can children use this BMI calculator?
No. Children and teens need age- and sex-specific BMI percentiles.
How can I lower my BMI?
A balanced diet, regular activity and good sleep. Our Calorie Calculator can help you set a daily target.
This bmi calculator is 100% free, needs no signup and works on phones, tablets and computers. Your data is processed in your browser and never uploaded.
Last updated: · By NodifyTech