Calculators
BMI Calculator
Estimate Body Mass Index from height and weight.
About the BMI Calculator
The BMI Calculator estimates your Body Mass Index from your weight and height, in kg and cm or in pounds, feet and inches. A colour gauge shows where you fall, and you can switch between the Indian / Asian cut-offs and the WHO cut-offs. It also shows the healthy weight range for your height.
What you can do with the BMI Calculator
- Metric or imperial: kg and cm, or pounds, feet and inches.
- Colour gauge: See where you fall from underweight to obese.
- Indian or WHO cut-offs: Switch to the lower Asian thresholds with one tap.
- Healthy range: Shows the healthy weight range for your height.
How BMI is calculated
BMI is your weight in kilograms divided by the square of your height in metres. For someone who weighs 70 kg and is 1.75 m tall, that's 70 ÷ (1.75 × 1.75) = 22.9. The World Health Organization's adult categories are: under 18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, and 30 or more obese.
Lower cut-offs for Asian populations
People of South Asian and East Asian descent tend to face higher health risks at lower BMI values, so Indian guidelines treat 23–24.9 as overweight and 25 or above as obese. That's why the calculator starts on the Indian / Asian scale; tap "WHO scale" to compare.
What BMI can't tell you
BMI doesn't distinguish muscle from fat, so athletes can score as overweight while being very healthy. It also doesn't show where fat is carried, which matters for health. It's not designed for children and teenagers, who need age-specific charts, or for pregnancy. Treat it as a starting point for a conversation with a doctor, not a diagnosis.
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Frequently Asked Questions
What is a healthy BMI?
For most adults, 18.5 to 24.9 by WHO standards. On the Indian / Asian scale, 18 to 22.9. The "Healthy weight for you" box turns that range into kilograms for your height.
Can I use pounds and feet?
Yes. Tap "lb · ft/in" and enter your weight in pounds and your height in feet and inches.
Can I use this BMI calculator for my child?
No. Children's BMI has to be compared with growth charts for their age and sex, so ask a paediatrician.
Why is my BMI high when I'm muscular?
Muscle is dense and heavy, and BMI only looks at total weight. A waist measurement or body-fat assessment gives a better picture for muscular people.
What is the BMI formula in pounds and inches?
BMI = 703 x weight in pounds / (height in inches) squared. For 154 lb and 5 ft 7 in (67 inches), that is 703 x 154 / 4,489 = about 24.1. The tool converts pounds and feet to kilograms and metres for you when you choose lb and ft/in.
Why are the Indian / Asian BMI cut-offs lower?
Studies show many South Asians have higher body fat and higher risk of diabetes and heart disease at a lower BMI than Europeans. Indian guidelines therefore treat 23 to 24.9 as overweight and 25 or more as obese, instead of the WHO cut-offs of 25 and 30.
What does "Prime (BMI 22)" mean?
It shows the weight that would give you a BMI of exactly 22, which sits in the middle of the normal range on both scales. For a height of 170 cm that is about 63.6 kg. Treat it as a reference point, not a target set for you.
How is the healthy weight range for my height worked out?
The tool multiplies your height in metres, squared, by the lower and upper limits of the normal BMI band. For 170 cm on the Indian scale, 18 x 2.89 to 22.9 x 2.89 gives about 52.0 to 66.2 kg. On the WHO scale it is about 53.5 to 72.0 kg.
Is waist size a better measure than BMI?
Waist size adds information BMI misses, because fat around the stomach carries more health risk. Indian guidelines commonly flag a waist over 90 cm for men and over 80 cm for women. A doctor can look at both together with other tests.
Is BMI accurate for older adults or during pregnancy?
BMI is less reliable for older adults, who often lose muscle, and it is not used to judge weight during pregnancy. The tool notes it is a screening number, not a diagnosis. For these situations, ask a doctor how to assess a healthy weight.
Is my weight or height saved anywhere?
No. The BMI is worked out by JavaScript in your browser as you move the sliders, and the numbers are not sent to a server or stored by this tool. Close or refresh the page and the sliders go back to their defaults.
Read the guide
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