BMI Calculator

The BMI Calculator gives a quick check of body mass index from height, weight, age and gender. It is a guide, not a health verdict, and it takes less than a minute.

Enter height, weight, age and gender to get the BMI, the weight category and an estimated body fat percentage. Your numbers stay in your browser. Nothing is sent anywhere and nothing is saved.

How to Use

1. Enter height in centimetres. If height is known in feet, convert it first. One foot is about 30.48 centimetres, so 5 feet 9 inches is about 175 centimetres.
2. Enter weight in kilograms. If weight is known in pounds, divide by 2.2. So 154 pounds is about 70 kilograms.
3. Enter age, choose gender and press Calculate. The BMI, the weight category and the body fat estimate appear below the buttons. For example, a 30-year-old man who weighs 70 kilograms and is 175 centimetres tall has a BMI of 22.9, which is classed as Normal weight.

What BMI Means

BMI is a rough guide to weight in relation to height. A BMI below 18.5 is classed as underweight, 18.5 to 24.9 is a healthy weight, 25 to 29.9 is overweight, and 30 or above is classed as obese. BMI does not suit everyone. It does not take muscle mass into account, so athletes and very muscular people may get a high reading even though they are not overweight. It is best used as a starting point, not as a medical verdict.

Key Features

• Gives BMI, weight category and estimated body fat in one calculation.
• Uses height, weight, age and gender for a more complete result.
• Runs in the browser with no sign-up and no download.
• Works on desktop, tablet and mobile.

Frequently Asked Questions

What is a healthy BMI?

Most guides put a healthy BMI between 18.5 and 24.9. That is a wide range, and where a person sits in it depends on build, age and health. The safest step is to check the overall picture with a healthcare professional.

Is the body fat percentage exact?

No, it is an estimate worked out from BMI, age and gender. It can give a rough idea, but it is not a measurement. A body fat scale or a skinfold test gives a more precise figure.

Is the BMI Calculator free?

Yes. The tool is free to use, with no sign-up and no account.

Related Tools

Also in Calculators: the Percentage Calculator works out percentage amounts, increases and decreases. Browse the rest of the collection in All Tools.