Home › Tools

BMI Calculator

Enter your height and weight to get your BMI, category and guidance in one click.

How to use the BMI Calculator

  1. Enter your height in cm — for example 170. If you know it in feet, see the conversion method below.
  2. Enter your weight in kg — for example 65.
  3. Press Calculate My BMI — your BMI, category and guidance appear instantly.

Understanding your BMI result

BMI (Body Mass Index) is your weight in kilograms divided by the square of your height in metres. It is the fastest screening number doctors, gyms and insurers use to classify body weight.

Here is the full classification the calculator uses, based on WHO guidelines:

BMI RangeCategoryWhat it suggests
Below 18.5UnderweightMay need nutritional support
18.5 – 24.9Normal weightHealthy range — maintain it
25.0 – 29.9OverweightDiet and activity review
30.0 and aboveObeseProfessional guidance advised

Your BMI is a starting point, not a verdict. Trends matter more than a single reading — measure monthly, not hourly.

Height in feet? Convert first

If you know your height in feet and inches, convert it to centimetres: multiply feet by 30.48 and inches by 2.54. For example, 5'7" = (5 × 30.48) + (7 × 2.54) = 170.18 cm. You can also use our free unit converter.

Limitations you should know

BMI does not distinguish muscle from fat. Athletes and bodybuilders often classify as “overweight” despite low body fat.

It is not calibrated for children (who need age-specific percentile charts), pregnancy, or adults over about 65 without adjustment.

Asian populations sometimes develop health risks at slightly lower BMI values; many Indian doctors use 23 as the overweight cut-off. Use BMI as one signal along with waist size, blood pressure and blood tests.

Frequently asked questions

What is a healthy BMI?
For most adults the healthy range is 18.5 to 24.9. Some Indian health authorities use 18.5–22.9 as the ideal band for South Asians.
Is BMI accurate for muscular people?
Not fully. Muscle weighs more than fat, so muscular people can show a high BMI while being perfectly healthy. Pair BMI with waist measurement for a better picture.
How do I calculate BMI manually?
BMI = weight (kg) ÷ height (m)². Example: 65 kg ÷ (1.70 × 1.70) = 22.5.
How often should I check my BMI?
Once a month is plenty. Weight fluctuates daily due to water, salt and food, so weekly obsessing is misleading.
Is this BMI calculator free?
Yes — free, unlimited, no sign-up. Your data stays in your browser.

Related tools

You might also find these useful: