Why are there two sets of BMI categories?

Many Asian populations develop weight-related conditions such as type 2 diabetes at a lower BMI, so lower thresholds are often used: overweight from 23 and obese from 25.

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Check your BMI, understand the number.

Enter your height and weight to see your Body Mass Index, which category it falls in, and the healthy weight range for your height — with both standard WHO and Asian cut-offs.

Units

Metric (cm, kg) Imperial (ft, lb)

Height

Weight

Age (optional)

yrs

Adult BMI categories apply from age 18. If you enter a younger age we'll flag it.

BMI categories for adults don't apply under 18. For children and teens, BMI is read against age- and sex-specific growth percentiles — please check with a doctor or a growth chart.

Classification

Standard (WHO) Asian cut-offs

Asian cut-offs flag health risk at a lower BMI (overweight from 23, obese from 25) and are commonly used for South Asian adults.

Your BMI

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BMI is a quick screening number, not a diagnosis. It can't tell muscle from fat or show where weight is carried, and it isn't designed for children, pregnancy or competitive athletes. For personal advice, talk to a doctor or dietitian.

Instant, as you type

Your BMI, category and healthy range update the moment you change a number — no calculate button.

Metric or imperial

Work in cm and kg, or feet, inches and pounds. Switch any time and your values convert automatically.

WHO and Asian cut-offs

See your result against the standard WHO categories or the lower Asia-Pacific thresholds.

Healthy range for your height

Not just a label — see the weight range that corresponds to a normal BMI at your height.

Download as PDF

Save a one-page report of your result to keep or share with your doctor or trainer.

Private by design

Everything is calculated in your browser. Your height and weight are never sent anywhere or stored.

BMI calculator: a quick check on weight for height

Body Mass Index (BMI) is a simple number that relates your weight to your height. It's widely used by doctors and health programmes as a first, quick screening step to see whether an adult's weight sits in a range linked with lower or higher health risk. Our BMI calculator gives you that number instantly, shows which category it falls in, and tells you the weight range that would be considered normal for your height.

How BMI is calculated

BMI = weight (kg) ÷ height (m)²
BMI = 703 × weight (lb) ÷ height (in)²

For example, someone who is 1.70 m tall and weighs 70 kg has a BMI of 70 ÷ (1.70 × 1.70) = 24.2.

BMI categories for adults

Category	Standard (WHO)	Asian cut-offs
Underweight	Below 18.5	Below 18.5
Normal	18.5 – 24.9	18.5 – 22.9
Overweight	25.0 – 29.9	23.0 – 24.9
Obese	30.0 and above	25.0 and above

Research has found that many Asian populations carry a higher risk of type 2 diabetes and heart disease at a lower BMI than people of European descent. That's why lower thresholds are often recommended for South Asian adults, and why this calculator lets you choose between the two.

How to use this calculator

Choose your units — metric (cm, kg) or imperial (feet, inches, pounds).
Enter your height and weight using the boxes or sliders.
Pick a classification — standard WHO or Asian cut-offs.
Read your result — your BMI, its category, and the healthy weight range for your height.
Download the PDF report if you'd like to keep or share it.

What BMI can't tell you

It doesn't separate muscle from fat, so a muscular person can score "overweight" while carrying little body fat.
It doesn't show where fat is stored — fat around the waist carries more health risk than fat elsewhere.
It isn't suited to children and teens, who are assessed against growth percentiles for their age and sex.
It isn't a good fit during pregnancy, and can read differently in older adults who have lost muscle.
Waist measurement, blood tests and a doctor's assessment give a fuller picture than BMI alone.

Who finds a BMI check useful

A quick health check-in

Get a rough sense of where your weight sits before a check-up.

Tracking over time

Re-check as your weight changes to see which direction the number is moving.

Conversations with a professional

Bring a printed report to a doctor, dietitian or trainer as a starting point.

Setting a realistic range

See the weight range that matches a normal BMI at your height.

Frequently asked questions

What is a healthy BMI?For adults, a BMI from 18.5 to 24.9 is considered normal under the standard WHO categories. With Asian cut-offs, the normal range is 18.5 to 22.9.

Why are there two sets of categories?Studies show that many Asian populations develop weight-related conditions such as type 2 diabetes at a lower BMI. The Asian cut-offs reflect that, flagging overweight from 23 and obesity from 25.

Is BMI accurate for athletes or very muscular people?Not always. Muscle weighs more than fat, so a muscular person can have a high BMI without excess body fat. In that case, body-fat percentage or waist measurement is more informative.

Does BMI apply to children and teenagers?The adult categories don't. For anyone under 18, BMI is compared with growth charts for their age and sex, which a doctor or paediatrician can do for you.

Does BMI differ for men and women?The adult formula and categories are the same for both. Body-fat distribution differs between men and women, which is one reason BMI is only a screening tool.

How is the healthy weight range worked out?It's the weight that would give a BMI of 18.5 at the bottom and the top of the normal range (24.9 for WHO, 22.9 for Asian cut-offs) at your height.

Is my data stored anywhere?No. Everything is calculated in your browser and nothing you enter is sent to a server.

This calculator is for general information only and is not medical advice or a diagnosis. Please speak to a qualified healthcare professional about your weight and health.