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What is my BMI?

Calculate your Body Mass Index and get personalized health insights in seconds

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UnderweightNormalOverweightObese
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BMI Prime
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Ponderal Index
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Healthy BMI

Your healthy weight range

For your height, a healthy weight is -

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What is BMI?

Body Mass Index is a measure of body fat based on height and weight. It applies to most adults aged 18-65.

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BMI limitations

BMI doesn't measure body fat directly. Athletes may have high BMI due to muscle mass. Always consult a doctor.

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Healthy range

A BMI between 18.5 and 24.9 is considered healthy for most adults according to the World Health Organization.

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Beyond BMI

Waist circumference, diet quality, and physical activity are also important indicators of overall health.

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Go deeper

Read BMI vs. Body Fat Percentage to see which number matters more for your goals, or check your daily calorie needs.

BMI categories

CategoryBMI Range
UnderweightBelow 18.5
Normal weight18.5 - 24.9
Overweight25.0 - 29.9
Obese class I30.0 - 34.9
Obese class II35.0 - 39.9
Obese class III40.0 and above

How BMI is actually calculated

BMI uses a straightforward formula developed by Belgian mathematician Adolphe Quetelet in the 1830s — long before it was adopted as a health screening tool. The formula is:

BMI = weight (kg) / height (m)²

In imperial units: BMI = (weight in lbs x 703) / height in inches²

For example, a person who is 5'9" (175cm) and weighs 160 lbs (72.5kg) has a BMI of 23.6 — squarely in the normal range. The same person at 185 lbs would have a BMI of 27.3, crossing into overweight.

What the BMI categories actually mean

The WHO classifications most people know are based on studies of predominantly European adult populations. Here is what each category means in practice — and where the research gets more nuanced:

BMI categories — WHO classification with context
CategoryBMI rangeHealth risk
UnderweightBelow 18.5Increased risk of nutritional deficiency, osteoporosis, immune issues
Normal weight18.5 – 24.9Lowest risk for most chronic diseases in most populations
Overweight25.0 – 29.9Modestly increased risk — research shows fit people in this range often have good outcomes
Obese class I30.0 – 34.9Increased risk of type 2 diabetes, heart disease, hypertension
Obese class II35.0 – 39.9High risk — significant cardiovascular and metabolic impact
Obese class III40.0 and aboveVery high risk — also called severe or morbid obesity
Important nuance

For people of Asian descent, health risks associated with excess body fat appear at lower BMI values. The WHO suggests considering action points at BMI 23 (overweight) and 27.5 (obese) for Asian populations, compared to 25 and 30 for other groups.

Where BMI falls short — and what to use instead

BMI has one major blind spot: it cannot distinguish between fat mass and muscle mass. A 200 lb person who is 5'10" has a BMI of 28.7 whether they are a competitive athlete or sedentary. The number is identical; the health picture is completely different.

Athletes and muscular people

May register as overweight or obese despite low body fat. Muscle is denser than fat, pushing BMI higher without any health risk.

Older adults

Tend to lose muscle and gain fat with age. BMI may look normal while body fat percentage is actually elevated — a condition called "normal weight obesity."

Shorter people

BMI tends to underestimate fatness in shorter individuals. The squaring of height in the formula doesn't scale perfectly across all body sizes.

Better alternatives

Waist-to-height ratio, waist circumference, and body fat percentage give a more complete picture of health risk than BMI alone.

Healthy weight ranges by height

Based on the WHO normal BMI range of 18.5 to 24.9, here are the healthy weight ranges for common heights:

Healthy weight range by height (BMI 18.5 – 24.9)
HeightHealthy weight rangeMidpoint
5'0" (152cm)95 – 128 lbs (43 – 58 kg)111 lbs
5'4" (163cm)108 – 145 lbs (49 – 66 kg)127 lbs
5'6" (168cm)115 – 154 lbs (52 – 70 kg)135 lbs
5'9" (175cm)125 – 168 lbs (57 – 76 kg)147 lbs
6'0" (183cm)136 – 183 lbs (62 – 83 kg)160 lbs
6'2" (188cm)144 – 194 lbs (65 – 88 kg)169 lbs

Common questions

How do I calculate my BMI?

Enter your weight and height above and click "Calculate my BMI." The calculator instantly shows your BMI score, category, and healthy weight range for your height.

What is a healthy BMI?

For most adults, a BMI between 18.5 and 24.9 is considered healthy. Below 18.5 is underweight, 25-29.9 is overweight, and 30 or above is obese.

Is BMI accurate for everyone?

BMI is a useful screening tool but has limitations. It may overestimate body fat in athletes and underestimate it in older adults. It also does not account for muscle mass, bone density, or fat distribution.

What is BMI Prime?

BMI Prime is your BMI divided by 25 (the upper limit of normal BMI). A BMI Prime of 1.0 means you are exactly at the upper limit of the healthy range. Below 1.0 is healthy or underweight, above 1.0 is overweight or obese.

How much should I weigh for my height?

The healthy weight range depends on your height. Our calculator shows your personalized healthy weight range based on the normal BMI range of 18.5 to 24.9.

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