BMI Chart for Adults: What Your Number Means

How BMI Is Calculated

BMI is calculated by dividing a person's weight by the square of their height. There are two versions of the formula depending on which unit system you use:

Metric Formula

BMI = weight (kg) / height (m)²

Example: A person weighing 70 kg who is 1.75 m tall has a BMI of 70 / (1.75 × 1.75) = 70 / 3.0625 = 22.9.

Imperial Formula

BMI = (weight (lbs) × 703) / height (inches)²

Example: A person weighing 155 lbs who is 5'9" (69 inches) has a BMI of (155 × 703) / (69 × 69) = 108,965 / 4,761 = 22.9.

Both formulas produce the same result. The factor of 703 in the imperial formula is simply a conversion constant that accounts for the difference between metric and imperial units. For instant calculations, use our BMI calculator.

BMI Categories and Health Risks

The World Health Organization (WHO) defines four primary BMI categories for adults. Understanding what each category means — and the health risks associated with it — is essential for interpreting your BMI correctly.

Underweight (BMI Below 18.5)

Being underweight carries its own set of health risks that are often overlooked in a culture focused on weight loss. Underweight individuals face increased risk of nutritional deficiencies (particularly iron, vitamin D, and calcium), weakened immune function leading to more frequent infections, osteoporosis and increased fracture risk, fertility problems in women (irregular or absent periods), and complications during surgery or illness due to lack of body reserves. Causes of being underweight include genetic factors, eating disorders, hyperthyroidism, celiac disease, chronic infections, and certain medications. If your BMI consistently falls below 18.5, a medical evaluation is warranted.

Normal Weight (BMI 18.5 to 24.9)

A BMI in the normal range is associated with the lowest overall risk of weight-related health conditions. People in this range generally have healthier blood pressure, blood sugar, and cholesterol levels. However, a normal BMI does not guarantee good health — someone can have a normal BMI while being physically unfit, having a poor diet, or carrying excess visceral fat around their organs. Lifestyle factors like physical activity, diet quality, sleep, and stress management matter as much as the number on the scale.

Overweight (BMI 25.0 to 29.9)

The overweight category encompasses a wide range of body compositions. Some people in this range are genuinely carrying excess body fat that increases their health risk, while others — particularly those who exercise regularly — may have a higher BMI due to muscle mass. Research indicates that moderately overweight individuals who are physically active and metabolically healthy may not face significantly elevated health risks compared to normal-weight individuals. However, a BMI in this range combined with a sedentary lifestyle, large waist circumference, elevated blood pressure, or high blood sugar does warrant attention. Use our body fat calculator to get a more nuanced picture of your body composition.

Obese (BMI 30.0 and Above)

Obesity is associated with a significantly increased risk of numerous serious health conditions. The risk increases progressively through the three obesity classes. Key health risks include type 2 diabetes (risk is 7 to 12 times higher compared to normal weight), heart disease and stroke, high blood pressure, several types of cancer (including colorectal, breast, endometrial, and kidney), sleep apnea and breathing difficulties, osteoarthritis from excess joint stress, gallbladder disease, fatty liver disease, and mental health effects including depression and reduced quality of life. It is important to note that weight loss of even 5 to 10 percent of body weight can produce meaningful improvements in many of these risk factors.

BMI Chart by Height and Weight

The following table shows BMI values for various height and weight combinations. Find your height in the left column and follow the row across to your weight (or the nearest value) to find your approximate BMI. Values are color-coded: underweight, normal, overweight, and obese ranges are indicated.

Reading the chart: A person who is 5'6" and weighs 160 lbs has a BMI of 25.8, which falls in the overweight category. A person who is 5'10" and weighs 180 lbs has a BMI of 25.8 — also overweight but at the low end of the range. A person who is 6'0" and weighs 180 lbs has a BMI of 24.4, which is in the normal range.

Normal Weight Ranges by Height

For quick reference, here are the weight ranges that correspond to a "normal" BMI (18.5 to 24.9) for each height:

Notice that the normal weight range spans approximately 30 to 49 pounds depending on height, which reflects the natural variation in body frames and composition among people of the same height. To find your personal ideal weight, try our ideal weight calculator.

Limitations of BMI: What It Cannot Tell You

While BMI is a useful screening tool, it has significant limitations that are important to understand. Relying solely on BMI for health decisions can be misleading.

Muscle Mass

BMI cannot distinguish between muscle and fat. Since muscle is denser than fat, a muscular person weighs more than a non-muscular person of the same height and body fat level. This means that athletes, bodybuilders, and anyone who engages in significant strength training may have a BMI in the overweight or even obese range while having a perfectly healthy body fat percentage. For example, many NFL players have BMIs above 30, and even lean athletes like basketball players often register as "overweight" by BMI standards.

Age

The standard BMI categories were developed primarily for adults aged 20 to 65. As people age, they tend to lose muscle mass (a process called sarcopenia) and gain fat mass, even if their weight stays the same. This means an older adult with a "normal" BMI may actually have an unhealthily high body fat percentage. Conversely, research suggests that being slightly overweight (BMI 25 to 27) in older age may offer a survival advantage, possibly because extra reserves help during illness or surgery.

Ethnicity and Body Composition

BMI does not account for ethnic differences in body composition and fat distribution. Research has shown that at the same BMI, Asian populations tend to have higher body fat percentages and a greater risk of type 2 diabetes and cardiovascular disease compared to White populations. This has led the WHO to propose lower BMI cutoffs for Asian populations — with overweight starting at 23 rather than 25, and obesity starting at 27.5 rather than 30. Conversely, some studies suggest that certain Pacific Islander and Black populations may have lower body fat percentages at the same BMI compared to White populations.

Fat Distribution

Where you carry your fat matters as much as how much fat you carry, and BMI tells you nothing about fat distribution. Visceral fat (fat stored around your internal organs in the abdominal area) is far more metabolically dangerous than subcutaneous fat (fat stored under the skin). Two people with identical BMIs can have very different health risk profiles depending on their fat distribution — someone with most of their fat around their midsection faces higher risks than someone whose fat is more evenly distributed.

Gender

Women naturally have a higher body fat percentage than men at any given BMI. A healthy body fat percentage for women is approximately 21 to 33 percent, while for men it is 8 to 21 percent. Despite this significant difference in body composition, the standard BMI categories use the same cutoffs for both sexes. This means BMI may slightly overestimate health risk for muscular men and slightly underestimate it for women with high body fat but average weight.

Waist Circumference: A Key Supplement to BMI

Because BMI cannot measure fat distribution, health professionals often use waist circumference as a complementary measurement. Waist circumference is a better indicator of visceral (abdominal) fat, which is more closely linked to metabolic disease than total body fat.

To measure your waist circumference correctly: stand up straight, find the top of your hip bone, place the tape measure evenly around your bare abdomen at the level of the navel (belly button), and read the measurement after exhaling normally. Do not pull the tape tight — it should be snug but not compressing the skin.

The combination of BMI and waist circumference provides a much better health risk assessment than either measurement alone. For example, a person with a normal BMI but a high waist circumference (indicating visceral fat accumulation) may actually face higher health risks than a person with an overweight BMI but a normal waist circumference.

Other Body Composition Measurements

If you want a more complete picture of your body composition beyond BMI and waist circumference, several other methods are available:

• Body fat percentage: Measured via skinfold calipers, bioelectrical impedance (BIA) scales, or DEXA scans. This tells you the actual proportion of your body weight that is fat versus lean tissue. A healthy body fat range for men is approximately 10 to 22 percent, and for women approximately 20 to 33 percent. Use our body fat calculator for an estimate.
• DEXA scan: Dual-Energy X-ray Absorptiometry is considered the gold standard for body composition measurement. It provides precise measurements of bone density, lean tissue, and fat mass for each region of your body. DEXA scans cost 50 to 200 and are available at hospitals, research facilities, and some fitness centers.
• Waist-to-hip ratio: Dividing your waist circumference by your hip circumference. A ratio above 0.90 for men or 0.85 for women indicates increased health risk.
• Waist-to-height ratio: Your waist circumference divided by your height. A ratio above 0.5 (meaning your waist is more than half your height) suggests increased cardiometabolic risk, regardless of BMI.
• Hydrostatic weighing: Underwater weighing that measures body density to calculate body fat percentage. Very accurate but requires specialized equipment and is less convenient than other methods.

When to Talk to Your Doctor About BMI

While BMI is not a diagnostic tool, certain BMI readings should prompt a conversation with your healthcare provider:

• BMI below 18.5: Discuss potential causes of being underweight, including nutritional deficiencies, thyroid disorders, eating disorders, or underlying medical conditions.
• BMI of 25 or above with risk factors: If your BMI is in the overweight or obese range and you also have high blood pressure, high cholesterol, high blood sugar, a family history of heart disease or diabetes, or a large waist circumference, discuss weight management strategies with your doctor.
• BMI of 30 or above: A BMI in the obese range warrants a medical conversation regardless of other risk factors, to assess current health status and discuss options for reducing health risks.
• Rapid weight changes: Unintentional weight gain or loss that changes your BMI by more than 2 to 3 points over a few months deserves medical attention, as it may indicate an underlying health issue.
• BMI seems inconsistent with your health: If you are muscular with a high BMI but feel healthy, or if you have a normal BMI but feel unwell, discuss additional body composition measurements or health screenings with your provider.

Remember that BMI is a starting point for health assessment, not the final word. Your doctor will consider BMI alongside your complete medical history, physical examination, blood work, lifestyle factors, and family history to form a comprehensive picture of your health.

BMI Across Different Countries and Populations

Average BMI varies significantly across the world, reflecting differences in diet, lifestyle, genetics, and economic development. According to WHO data:

These population-level differences underscore why universal BMI cutoffs may not be equally appropriate for all ethnic groups and why the modified Asian BMI thresholds mentioned earlier are important for accurate health assessment in those populations.

Frequently Asked Questions