BMI (Body Mass Index) is a simple number calculated from your weight and height. It gives a rough estimate of whether your weight is in a healthy range for your height. It is used by doctors, health organizations, and fitness professionals worldwide as a quick screening tool.

How is BMI calculated?

The formula is: BMI = weight in kilograms divided by height in meters squared (kg/m²). For example, if you weigh 70 kg and are 1.75 m tall, your BMI is 70 ÷ (1.75 × 1.75) = 22.9. In the imperial system, the formula is BMI = 703 × weight in pounds ÷ height in inches squared.

What is a healthy BMI range?

According to the World Health Organization (WHO), a healthy BMI is between 18.5 and 24.9. Below 18.5 is considered underweight, 25–29.9 is overweight, and 30 or above is obese. These ranges apply to most adults aged 20 and older.

Does BMI differ for men and women?

The BMI formula itself is the same for both men and women. However, women naturally tend to have a higher body fat percentage at the same BMI compared to men. The WHO categories apply to both genders, but interpretation may vary slightly.

BMI Prime is your BMI divided by 25 (the upper limit of the healthy range). A BMI Prime of 1.0 means you are exactly at the upper healthy limit. Below 1.0 is healthy, above 1.0 indicates overweight, and above 1.2 indicates obesity. It is a quick way to see how far you are from the healthy range.

Should I rely on BMI for health decisions?

BMI is a useful starting point, but it should not be the only factor. For a complete picture of your health, combine BMI with other measurements like waist circumference, body fat percentage, blood pressure, and blood tests. Always consult a qualified healthcare professional before making health decisions.

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BMI Calculator

Q: Is BMI accurate for everyone?

No. BMI is a general indicator and has limitations. It does not distinguish between muscle and fat, so athletes with high muscle mass may be classified as overweight despite being very healthy. It is also less accurate for elderly people, pregnant women, and children, who use different charts.

Q: What is the Ponderal Index?

The Ponderal Index is an alternative to BMI, calculated as weight in kilograms divided by height in meters cubed (kg/m³). It is considered more accurate for very tall or very short people because BMI tends to overestimate fat in tall individuals and underestimate it in short ones.

Calculate your Body Mass Index (BMI) and see your weight category.

Weight (kg)

Height (cm)

💡 BMI is a general indicator and does not distinguish between muscle and fat. Consult a doctor for a complete health assessment.

About Our BMI Calculator

Body Mass Index (BMI) is one of the most popular ways to determine health. It is commonly used by doctors, nutritionists, fitness trainers and insurance companies as a simple way to determine if someone is within the healthy weight range for their height. This calculator can be used by anyone.

This calculator will tell you your BMI score, weight category and healthy weight range for your height. Simply input your weight and height to instantly know. We support metric (kg/cm), imperial (lb/ft+in) and India friendly (kg/ft+in). Calculated on your device with no data sent to a server.

How To Use Our BMI Calculator

To find your BMI:

Select your unit (Metric (kg/cm) for most countries, Metric (ft+in) for India and similar countries or Imperial (lb/ft+in) for the US and UK).
Input your weight into the box. The unit will change based on what you selected.
Input your height in CM or FT+IN.
Your results will instantly show. You'll see your BMI score, colour coded weight category (Underweight, Normal, Overweight, Obese) and healthy weight range.

Why Should I Use This BMI Calculator?

There are many BMI calculators available. However, ours provides...

Three Unit Options. While most BMI calculators offer metric or imperial options, we also provide a popular kg/ft+in option.
Extra Information. Alongside your BMI score we also show your BMI Prime and Ponderal Index scores.
Healthy Weight Range. We calculate what your healthy weight range is to ensure you fall into the healthy BMI range for your height.
Private. All calculations are completed on your device. We do not store your weight or height.
Instant & Free. No sign up, no annoying ads and instant results.

BMI Categories

According to the World Health Organization (WHO) there are 4 main categories:

Underweight (<18.5). This may indicate you're suffering from malnutrition, eating disorders or an underlying health issue. It may be worth speaking to your doctor to rule out any medical conditions.
Normal Weight (18.5-24.9). This is the healthiest range for most adults. You have the lowest risk of weight related diseases.
Overweight (25-29.9). This increases your risk of heart disease, high blood pressure and type 2 diabetes. Changing your lifestyle could help.
Obese (30+). This significantly increases your risk of health issues. It is strongly recommended to speak to a medical professional.

Issues With BMI

While BMI is a useful tool, it does have its limitations. As BMI simply compares your weight to your height it doesn't actually measure body fat. This can cause issues for athletes with lots of muscle. They often receive an overweight result when they're extremely fit. Older people also may receive a normal BMI even though they have unhealthy amounts of visceral fat.

BMI is also not accurate for children/teenagers (they require age and gender specific charts), pregnant women and some ethnicities. BMI should be used alongside Waist Circumference, Body Fat %, Blood Pressure and regular visits to your doctor for an accurate picture of your health.

FAQs

What Is BMI?

BMI stands for Body Mass Index. It's simply a number calculated using your weight and height. It gives you a general idea of if you're within a healthy weight range for your height. It's used globally by doctors, health organisations and fitness professionals.

How Do I Calculate My BMI?

The formula is BMI = kg/m² (Weight divided by Height Squared). For example, if you weigh 70kg and are 1.75m tall: 70 / (1.75 x 1.75) = 22.9. For imperial it's BMI = 703 x (pounds / Inches Squared).

What Is A Healthy BMI?

According to the World Health Organization (WHO), a healthy BMI is between 18.5 and 24.9. If you're below 18.5 you're underweight. Between 25-29.9 you're overweight. If you're 30 or above you're obese. This is for most adults aged 20+.

Is BMI Accurate For Everyone?

No. It's a general guide. As it doesn't differentiate muscle and fat, athletes with high muscle mass may receive an overweight result when they are extremely healthy. It's also less accurate for the elderly, pregnant women and children.

Is BMI Different For Men And Women?

The formula for BMI is the same for males and females. However women naturally have a higher body fat % than males. The WHO categories apply to both genders.

What Is BMI Prime?

BMI Prime is simply your BMI divided by 25 (The max healthy range). If your BMI Prime is 1.0 then you're right at the top of your healthy range. Less than 1.0 means you're in a healthy range. Greater than 1.0 means you're overweight. Greater than 1.2 means you're obese. It's a quick way to see where you fall in relation to the healthy range.

What Is The Ponderal Index?

The Ponderal Index is an alternative to BMI. It's calculated by dividing your weight (kg) by your height (m) cubed. It's seen as more accurate for very tall or short people as BMI tends to overestimate fat for tall people and underestimate for short people.

Should I Use BMI?

While BMI is a useful tool to start with, it shouldn't be relied upon. Use alongside other measurements such as Waist Circumference, Body Fat %, Blood Pressure and blood tests. Always consult a qualified health professional.

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