BMI Calculator — check your (or your parents') body mass index

Q: My BMI is normal — do I still need a checkup?

Yes. A healthy BMI does not rule out high blood sugar, cholesterol, thyroid or vitamin issues, which often have no symptoms. A preventive checkup looks beyond weight to the numbers you cannot see.

Q: How often should BMI be checked?

Once a year is sensible for most adults, and it pairs naturally with an annual preventive health checkup so any change is caught early.

Height

Weight

Gender (optional)

Age (optional)

Your BMI and category will appear here once you calculate.

This calculator is an informational screening tool for adults and is not a medical diagnosis. Speak with a doctor about what a healthy weight means for you.

The basics

What is BMI?

Body Mass Index is a simple ratio of weight to height that estimates whether a person is underweight, at a healthy weight, overweight, or living with obesity. Because it needs only two numbers, it's one of the quickest ways to flag a possible weight-related health risk — which is why doctors often use it as a first screen before deeper tests.

BMI doesn't measure body fat directly and it doesn't tell the whole story on its own. But paired with blood work and a doctor's review — the way a full preventive checkup works — it's a useful starting point for a conversation about heart, metabolic, and joint health.

The formula

How is BMI calculated?

BMI divides body weight in kilograms by the square of height in metres:

BMI = weight (kg) ÷ height (m)²

Example: a person who is 165 cm (1.65 m) tall and weighs 68 kg has a BMI of 68 ÷ (1.65 × 1.65) = 24.98 — at the top of the healthy range. The calculator above does this for you, in metric or imperial units.

Reading the number

BMI categories for adults

The World Health Organization (WHO) uses these ranges for adults:

Category	BMI range (kg/m²)
Underweight	Below 18.5
Healthy weight	18.5 – 24.9
Overweight	25.0 – 29.9
Obese	30.0 and above

A note for India: Indian and other South Asian populations can carry higher health risk at a lower BMI. Revised Indian guidelines often treat 23.0 and above as overweight and 25.0 and above as obese. If your BMI is in the 23–25 band, it's worth discussing with a doctor even though the WHO chart above calls it "healthy."

Why it matters

Why BMI matters for your parents

For older adults, weight sits at the centre of many everyday health risks. A BMI on the higher side is linked to raised blood pressure, type-2 diabetes, joint pain and heart disease. A BMI that's too low can signal poor nutrition, muscle loss or an underlying condition — and can slow recovery from illness.

Because weight changes gradually, a yearly BMI check — alongside blood sugar, cholesterol, thyroid and vitamin levels — helps catch a shift early, while it's easy to act on. That's exactly the kind of picture a Parent Health preventive checkup puts together, with a doctor to explain what it means.

Keep in mind

Limitations of BMI

It doesn't distinguish muscle from fat, so very muscular people can read as "overweight."
It says nothing about where fat is stored — waist size is a better guide to belly fat and heart risk.
In older adults, height loss and muscle changes can make BMI less accurate.
It's a screen, not a diagnosis — always read it alongside blood work and a doctor's assessment.

Questions

BMI — frequently asked

What is a healthy BMI?

For most adults, a BMI between 18.5 and 24.9 is considered healthy by WHO. For Indian populations, staying under 23 is often advised because health risks can begin earlier.

Is BMI the same for men and women?

The BMI formula and adult categories are the same for men and women. Body composition differs between individuals, which is one reason BMI is a screen rather than a complete measure of health.

Does BMI work for older adults?

BMI still gives a useful signal for seniors, but height loss and reduced muscle mass can affect the reading. For older parents, it's best interpreted together with blood tests, waist measurement and a doctor's review.

My BMI is normal — do I still need a checkup?

Yes. A healthy BMI doesn't rule out high blood sugar, cholesterol, thyroid or vitamin issues, which often have no symptoms. A preventive checkup looks beyond weight to the numbers you can't see.

How often should BMI be checked?

Once a year is a sensible rhythm for most adults, and it pairs naturally with an annual preventive health checkup so any change is caught early.

Numbers are clearer with a doctor beside them.

A Parent Health preventive checkup pairs your parents' vitals and blood work with a doctor who explains every result in plain language.

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