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BMI Chart & Table : Complete WHO Classification
The complete WHO BMI classification used by the CDC and NHS, with US prevalence data: 41.9% of American adults are obese (NHANES 2017-2020).
The body mass index table reproduces the international classification published by the World Health Organization: underweight below 18.5, normal build up to 25, overweight up to 30, then three classes of obesity, from 30 to 35, from 35 to 40 and above 40. That split of obesity guides treatment, with bariatric surgery entering the options above 40, or above 35 with an associated complication. The thresholds are conventions, not biological borders: nothing changes in the body between 24.9 and 25.1. Several Asian countries indeed apply lowered values, with overweight starting at 23 and obesity at 27.5, because metabolic risk appears earlier there at comparable body composition. After 65 the table applies imperfectly, since height falls with age and muscle mass shrinks, and a target range of 23 to 28 is often preferred.
International BMI classification (adults)
| Classification | BMI (kg/m²) | Comorbidity risk |
|---|---|---|
Severe underweight | < 16.0 | High (malnutrition) |
Moderate underweight | 16.0 - 16.9 | Moderate |
Mild underweight | 17.0 - 18.4 | Low |
Normal weight | 18.5 - 24.9 | Low (reference) |
Overweight (pre-obesity) | 25.0 - 29.9 | Increased |
Obesity class I (moderate) | 30.0 - 34.9 | High |
Obesity class II (severe) | 35.0 - 39.9 | Very high |
Obesity class III (morbid) | ≥ 40.0 | Extremely high |
Source: World Health Organization (WHO), adopted by the CDC (United States) and NHS (United Kingdom)
Weight / height table (lbs & kg)
Correspondence between height and weight range for each BMI category. Heights shown in feet/inches with metric equivalent. US/UK average heights highlighted.
| Height | Underweight <18.5 | Normal 18.5-24.9 | Overweight 25-29.9 | Obesity ≥30 |
|---|---|---|---|---|
| 5'1" (155 cm) | <97 lbs (44 kg) | 97-132 lbs (44-60 kg) | 132-159 lbs (60-72 kg) | >159 lbs (72 kg) |
| 5'3" (160 cm) | <104 lbs (47 kg) | 104-141 lbs (47-64 kg) | 141-170 lbs (64-77 kg) | >170 lbs (77 kg) |
| 5'4" (163 cm)US/UK female avg. | <108 lbs (49 kg) | 108-148 lbs (49-67 kg) | 148-176 lbs (67-80 kg) | >176 lbs (80 kg) |
| 5'5" (165 cm) | <110 lbs (50 kg) | 110-150 lbs (50-68 kg) | 150-179 lbs (68-81 kg) | >179 lbs (81 kg) |
| 5'7" (170 cm) | <117 lbs (53 kg) | 117-159 lbs (53-72 kg) | 159-192 lbs (72-87 kg) | >192 lbs (87 kg) |
| 5'9" (175 cm)US male avg. | <126 lbs (57 kg) | 126-168 lbs (57-76 kg) | 168-203 lbs (76-92 kg) | >203 lbs (92 kg) |
| 5'11" (180 cm) | <132 lbs (60 kg) | 132-179 lbs (60-81 kg) | 179-214 lbs (81-97 kg) | >214 lbs (97 kg) |
| 6'1" (185 cm) | <139 lbs (63 kg) | 139-187 lbs (63-85 kg) | 187-225 lbs (85-102 kg) | >225 lbs (102 kg) |
| 6'3" (190 cm) | <148 lbs (67 kg) | 148-198 lbs (67-90 kg) | 198-238 lbs (90-108 kg) | >238 lbs (108 kg) |
Highlighted rows: 5'9" (175 cm) is the average US adult male height; 5'4" (163 cm) is the average US/UK adult female height.
US Prevalence by BMI Category
Distribution of BMI categories among American adults aged 20 and over, according to CDC/NHANES 2017-2020 survey data:
Source: CDC/NCHS, National Health and Nutrition Examination Survey (NHANES) 2017-2020.
US vs UK: BMI Statistics Comparison
Head-to-head comparison of obesity and overweight prevalence between the United States and the United Kingdom, the two largest English-speaking nations:
| Metric | United States | United Kingdom |
|---|---|---|
| Adult obesity rate (BMI ≥ 30) | 41.9% | 25.9% |
| Overweight + obese (BMI ≥ 25) | 73.6% | 63.8% |
| Annual healthcare cost of obesity | $173 billion/year | £6.5 billion/year |
| Data source | CDC / NHANES 2017-2020 | NHS Digital / Health Survey for England |
| 30-year trend | Steadily increasing since 1990s, from ~23% to 41.9% obese | Steadily increasing since 1990s, from ~15% to 25.9% obese |
Both countries have seen dramatic increases in obesity rates over the past three decades. The US consistently reports higher rates, partly due to differences in food regulation, portion sizes, and urban design.
Edge cases and exceptions
BMI is not suitable for:
- Muscular athletes: muscle mass = overestimated BMI. The CDC notes BMI may overestimate body fat in athletes and those with a muscular build.
- Pregnant women: normal weight gain during pregnancy is not factored into BMI thresholds
- Elderly people: age-related muscle mass loss (sarcopenia) can mask high body fat
- Children/teens: the CDC recommends age- and sex-specific BMI percentile charts for those under 20
Complementary indicators:
- Waist circumference: recommended by CDC and AHA to assess abdominal fat risk
- Body fat %: more accurate body composition assessment via DEXA or calipers
- Waist-to-hip ratio: evaluates fat distribution and cardiovascular risk
- FFMI: Fat-Free Mass Index, used for athletes and fitness assessments
Insurance note: Under the Affordable Care Act (ACA), BMI alone does not qualify for health insurance premium adjustments. Insurers cannot use BMI as the sole basis for rate changes, though employer wellness programs may include BMI-related incentives within ACA-defined limits.
Waist Circumference: AHA/CDC Guidelines
The American Heart Association (AHA) and CDC recommend waist circumference as a complementary measure to BMI for assessing metabolic risk. Note that US thresholds differ from the WHO/European guidelines:
Men
Note: The WHO/European threshold is stricter at 37 inches (94 cm). The US uses a higher cut-off based on research in predominantly Western populations.
Women
Note: This threshold is the same as the WHO guideline (88 cm / 35 inches). US and European recommendations align for women.
Why the difference? The US uses National Institutes of Health (NIH) guidelines from 1998, which set the male waist threshold at 40 inches (102 cm). The WHO and International Diabetes Federation (IDF) later adopted a stricter 37-inch (94 cm) threshold for men based on European data. Both agree that waist circumference, combined with BMI, provides a better predictor of cardiovascular and metabolic disease risk than BMI alone.
State-by-State Obesity Disparities in the US
Obesity prevalence varies dramatically across the United States, reflecting deep structural differences in income, food access, infrastructure, and demographics. According to CDC Behavioral Risk Factor Surveillance System (BRFSS) data, Mississippi holds the highest adult obesity rate at 40.8%, while Colorado reports the lowest at 25.1%, a gap of nearly 16 percentage points between the two states.
The Southern "Stroke Belt"
Southern states consistently rank among the highest for obesity prevalence. States like West Virginia, Alabama, Louisiana, and Arkansas all exceed 38% adult obesity. This region, historically called the "Stroke Belt" by the CDC, faces compounding factors: lower household incomes, fewer supermarkets per capita, higher rates of food insecurity, and limited access to recreational facilities. These environmental and socioeconomic conditions make healthy weight management significantly more challenging for residents.
Rural vs. Urban Divide
CDC data reveals a persistent rural-urban gap of 6.2 percentage points in adult obesity rates. Rural counties average roughly 36.5% obesity prevalence compared to about 30.3% in metropolitan areas. Contributing factors include longer distances to grocery stores and healthcare facilities, fewer walkable neighborhoods, and reduced access to fitness programs. The USDA has classified many rural areas as "food deserts," where residents must travel over 10 miles to reach a full-service supermarket.
Racial and Ethnic Disparities
Obesity affects racial and ethnic groups at significantly different rates in the US. CDC survey data shows that non-Hispanic Black adults have the highest prevalence at 49.9%, followed by Hispanic adults at 45.6% and non-Hispanic White adults at 41.4%. These disparities are driven not by genetics but by systemic inequities, including unequal access to affordable, nutritious food, disparities in healthcare coverage, neighborhood safety concerns that limit physical activity, and the lasting effects of residential segregation on community health infrastructure.
Poverty and obesity correlation: Research published by the CDC consistently demonstrates a strong association between state-level poverty rates and obesity prevalence. States with poverty rates above 20% tend to have obesity rates 5 to 8 percentage points higher than wealthier states. Limited financial resources reduce access to fresh produce, gym memberships, and preventive healthcare, creating a cycle where economic disadvantage directly fuels higher BMI across entire communities.
Understanding the BMI table: US & UK context
The WHO BMI table is the international reference for classifying body mass, adopted by both the CDC in the United States and the NHS in the United Kingdom. This body mass index table defines thresholds for underweight, normal weight, overweight and obesity, with the same cut-offs used worldwide.
According to NHANES 2017-2020 data, 41.9% of American adults have a BMI of 30 or above, making obesity a major public health concern tracked by the CDC. In the UK, NHS Digital reports 25.9% obesity prevalence. Both nations have seen rates roughly double over the past 30 years.
The BMI classification distinguishes three levels of underweight (severe, moderate, mild) and three obesity classes (I, II, III). The adult BMI table applies to people over 18 years old. For children, the CDC recommends age-specific percentile charts.
Beyond BMI, the American Heart Association (AHA) and CDC recommend measuring waist circumference as a complementary indicator of metabolic risk. US thresholds (40 inches for men, 35 inches for women) differ slightly from European WHO guidelines, particularly for men.
To interpret your result, consult the BMI correspondence table above, which shows weights in both pounds (lbs) and kilograms (kg). The weight height BMI table highlights US average heights, 5'9" for men and 5'4" for women, so you can quickly find your category. For a full picture of health risk, combine your BMI with waist circumference and body fat percentage assessments.
Frequently asked questions
Where do the BMI table categories come from?
From the international classification published by the World Health Organization. It sets underweight below 18.5, normal build up to 25, overweight up to 30, then three classes of obesity above that. The thresholds have been stable since the 1990s and serve as a common language between countries and studies.
Why is obesity split into three classes?
Because the associated risk differs. Class I runs from 30 to 35, class II from 35 to 40, class III above. The split guides treatment: above 40, or above 35 with an associated complication, bariatric surgery enters the options discussed by a multidisciplinary team.
Are the thresholds the same worldwide?
No. Several Asian countries apply lowered cut-offs, with overweight starting at 23 and obesity at 27.5, because metabolic risk appears at a lower BMI for comparable body composition. The values in our table are those of the international classification used in Europe.
How do you read the table when you sit between two categories?
The thresholds are conventions, not biological borders: nothing changes in the body between 24.9 and 25.1. A borderline value mainly invites you to look at the trend across several measurements and at waist circumference, which is more informative at that precise point on the scale.
Does the table apply to older people?
Imperfectly. After 65, height falls by one to three centimetres, which mechanically inflates the index, and muscle mass shrinks. Several medical bodies recommend a target range of 23 to 28: a small reserve protects during illness, whereas thinness worsens the outlook.
How many adults sit above 25?
Close to one adult in two in France, of whom roughly seventeen per cent above 30, according to the most recent national surveys. The proportion rises with age and varies sharply by socio-economic group. These figures describe a population; they say nothing about any one person's risk.
Written by Radif Partners
Éditeur de calculateurs et de guides pratiques