BMI Calculator — Body Mass Index United States
A quick health check — see where you sit on the scale.
Calculate US BMI and healthy-weight range with WHO categories, waist-target guidance, and CDC-style interpretation context.
United States BMI Notes
BMI is a screening tool, not a diagnosis, but it is still useful when combined with waist measurement, health history, and clinician advice.
This version is tuned to US users with CDC and NHLBI-style guidance around weight categories, waist measures, and when to seek medical follow-up.
US setup: this bmi is tuned for dollar-denominated scenarios, American payroll and tax references, state-by-state cost differences, and the finance terms people see in lender, employer, or IRS-facing documents.
The page keeps US language in place where it is relevant, including IRS, federal withholding, FICA, 401(k), sales tax, miles, APR, down payment, paycheck, state tax, and USD totals.
Treat the answer as a United States estimate; before acting, compare it with provider disclosures, state rules, federal guidance, lender underwriting, payroll settings, or advice from a qualified professional.
BMI is a population-level screening tool. It does not measure body fat % or account for muscle mass. Not a substitute for medical advice.
Select the question that matches where you are right now.
Your BMI is a ratio of weight to height squared. It is a population-level screening tool used to identify people who may be at increased risk of weight-related health conditions — not a medical diagnosis.
Associated with the lowest population-level risk of weight-related conditions such as type 2 diabetes, cardiovascular disease, and certain cancers. Maintaining this range through balanced eating and regular activity is the general health goal.
Moderately increased risk of several health conditions compared to healthy weight. Even modest weight loss of 5–10% has been shown to significantly improve metabolic markers (blood pressure, blood glucose, cholesterol) in this range.
Substantially increased risk of type 2 diabetes, heart disease, sleep apnoea, joint problems, and some cancers. However, risk varies significantly based on where fat is stored (waist circumference) and individual metabolic health.
BMI is a useful screening tool but has significant limitations. Understanding these helps you interpret your result accurately.
BMI cannot distinguish between fat and muscle. A lean athlete with high muscle mass may have a BMI of 28 (overweight) while having very low body fat. Conversely, a sedentary person with BMI 24 may have high body fat but low muscle mass — sometimes called "skinny fat".
Visceral fat (around abdominal organs) is more metabolically dangerous than subcutaneous fat. Two people with the same BMI can have very different health risks based on where they carry their weight. Waist circumference is a better predictor of cardiometabolic risk.
BMI thresholds were developed primarily from studies of European populations. Research shows that people of Asian descent develop metabolic disease at lower BMI values, while some Pacific and Indigenous populations may be healthy at higher BMIs. Use the standard WHO thresholds as a starting point, but discuss your specific situation with your GP.
If your BMI is outside the healthy range, the evidence-based approach focuses on sustainable lifestyle changes rather than rapid weight loss.
A modest daily deficit of 500kJ (120 calories) leads to roughly 0.5kg weight loss per month — about 6kg per year. This is sustainable and evidence-based. Crash diets cause rapid initial loss but have very high recidivism rates within 1–2 years.
Resistance exercise preserves or builds muscle while losing fat. This improves metabolic rate, functional capacity, and body composition — even when BMI doesn change much. Building muscle is one of the most evidence-based interventions for metabolic health.
Reducing waist circumference is more meaningful than reaching a BMI target. Even without significant weight loss, redistributing fat (losing visceral fat through diet and aerobic exercise) substantially reduces cardiometabolic risk. A waist measurement under 94cm (men) or 80cm (women) is the primary target.
If your BMI indicates a health concern, these are the most useful next steps in the US health system.
A GP can assess your actual health risk based on your full clinical picture — blood pressure, blood glucose, lipid profile, family history, and waist circumference. BMI alone is a starting point. Your GP can refer you to dietitians, exercise physiologists, or specialists as needed.
CDC the United States (CDC.gov) offers a nurse-led telephone health line (1-800-CDC-INFO), a body weight resource center, and referral to local services. The CDC also publishes US health statistics if you want to understand how your measurements compare to population data.
A Registered Dietitian Nutritionist (RDN) can create a personalised eating plan. A certified exercise physiologist or physical therapist can design a safe exercise program. Medicare Part B may cover medical nutrition therapy for people with diabetes or kidney disease; other insurance coverage varies — check your plan before booking.
The BMI formula, what it measures, and its limitations
The formula
Body Mass Index = Weight (kg) ÷ Height (m)². For example, 70kg at 170cm: BMI = 70 ÷ (1.70)² = 70 ÷ 2.89 = 24.2. The result places you in one of the WHO categories. Source: WHO — Obesity and overweight (fact sheet) and CDC — Adult BMI Calculator.
| BMI range | Category | Health risk |
|---|---|---|
| Under 18.5 | Underweight | Increased risk (malnutrition, bone density) |
| 18.5–24.9 | Healthy weight | Lowest risk for most conditions |
| 25.0–29.9 | Overweight | Moderately increased risk |
| 30.0–34.9 | Obese Class I | High risk (diabetes, CVD) |
| 35.0–39.9 | Obese Class II | Very high risk |
| 40.0+ | Obese Class III | Extremely high risk |
Limitations of BMI
BMI does not measure body fat percentage, muscle mass, or fat distribution. Athletes and people with high muscle mass often have elevated BMI with healthy body composition. BMI also does not distinguish where body fat is stored — visceral fat (around the abdomen) is more dangerous than subcutaneous fat, but BMI cannot identify this.
Average US BMI, obesity rates, and state differences
US averages
The average US adult BMI is approximately 27.2 — in the overweight range. About 67% of US adults are overweight or obese (BMI ≥ 25), placing the United States among the highest rates in the OECD. The CDC (through the National Center for Health Statistics) tracks these figures annually via NHANES. Source: CDC — Adult Obesity Facts and CDC NCHS — Obesity and Overweight (FastStats).
Trends
US obesity rates have been rising steadily. In the mid-1990s, about 23% of adults were obese (BMI ≥ 30); by 2021–2023, roughly 40% of US adults met the CDC obesity threshold. The largest absolute increases have been among adults aged 45–74. Rural adults have higher obesity rates than those in large metropolitan areas. Source: CDC NCHS Data Brief — Obesity in US Adults, 2021–2023.
Healthy weight ranges for common heights
| Height | Healthy weight range (BMI 18.5–24.9) |
|---|---|
| 155cm | 44.4–59.9kg |
| 160cm | 47.3–63.7kg |
| 165cm | 50.4–67.8kg |
| 170cm | 53.5–72.0kg |
| 175cm | 56.7–76.3kg |
| 180cm | 59.9–80.9kg |
| 185cm | 63.3–85.4kg |
Waist circumference, waist-to-height ratio, and body fat percentage
Waist circumference
Waist circumference is a better predictor of cardiovascular disease and type 2 diabetes risk than BMI alone. The reason: visceral fat (the fat stored around abdominal organs) is metabolically active and more dangerous than fat stored elsewhere. US NHLBI and WHO guidelines recommend:
- Men: under 102cm / 40in (high risk above that threshold under NHLBI)
- Women: under 88cm / 35in (high risk above that threshold under NHLBI)
- WHO action levels: increased risk at 94cm (men) / 80cm (women); substantially increased at 102cm / 88cm.
Sources: NHLBI — Assessing Your Weight and Health Risk and WHO — Waist Circumference and Waist–Hip Ratio: Report of a WHO Expert Consultation.
Waist-to-height ratio
A waist measurement greater than half your height is associated with significantly increased cardiometabolic risk. This simple calculation (waist ÷ height) should be under 0.5 for most adults. It accounts for body size in a way that waist circumference alone does not.
Body fat percentage
DEXA scans, hydrostatic weighing, or bioelectrical impedance (BIA) scales measure actual body fat percentage. Healthy ranges: men 10–20%, women 18–28% (varies by age). These are more accurate than BMI for assessing body composition but less accessible as screening tools.
Why different BMI thresholds may apply to Asian-US populations
The research basis
Population-level research has consistently shown that people of Asian descent develop metabolic risk factors (type 2 diabetes, hypertension, cardiovascular disease) at lower BMI values than people of European descent. This is partly due to differences in body fat distribution — Asian populations tend to accumulate more visceral fat at the same BMI. Source: WHO Expert Consultation, Lancet 2004 — Appropriate body-mass index for Asian populations.
Recommended lower cutoffs for Asian populations
| Category | Standard WHO (European) | Suggested Asian-specific |
|---|---|---|
| Healthy | 18.5–24.9 | 18.5–22.9 |
| At risk (overweight) | 25.0+ | 23.0+ |
| High risk (obese) | 30.0+ | 27.5+ |
These lower thresholds are used in some Asian countries (Singapore, Japan, Hong Kong) and are recommended by some US health practitioners for patients of Asian descent. This calculator uses standard WHO cutoffs — if you are of Asian descent, discuss lower thresholds with your doctor.
Frequently asked Frequently asked questions
What is a healthy BMI in the United States?
The US and WHO standard healthy BMI range is 18.5–24.9 for adults. Under 18.5 is underweight; 25–29.9 is overweight; 30 and above is obese. These cutoffs apply to people of European descent. For people of Asian descent, some health authorities recommend lower cutoffs (23 for overweight risk, 27.5 for obesity risk).
What is the average BMI in the United States?
The average US adult BMI is approximately 27.2, placing the average adult in the overweight category. About 67% of US adults are overweight or obese, and roughly 40% are obese (BMI 30+) according to CDC NHANES 2021–2023. These rates have been rising steadily since the 1990s. Source: CDC — Adult Obesity Facts.
Is BMI accurate for muscular people?
No. BMI does not distinguish between fat mass and muscle mass. A person with high muscle mass (such as an athlete or bodybuilder) may have a high BMI but low body fat percentage. For muscular individuals, waist circumference and body fat percentage are better indicators of health risk than BMI alone.
What BMI is considered obese in the United States?
A BMI of 30 or above is classified as obese by WHO and US health standards. Obesity is further divided into Class I (30–34.9), Class II (35–39.9), and Class III (40+, sometimes called severe obesity). Roughly 40% of US adults fall into the obese category per CDC NHANES. Source: CDC — Defining Adult Overweight & Obesity.
Where these figures come from
Health thresholds and US population statistics on this page are drawn from primary health authorities — the Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO), and the National Heart, Lung, and Blood Institute (NHLBI).
- Adult BMI formula & categories — WHO — Obesity and overweight fact sheet.
- CDC Adult BMI calculator — CDC — Adult BMI Calculator.
- US adult obesity prevalence (NHANES) — CDC — Adult Obesity Facts.
- Waist circumference thresholds — NHLBI — Assessing Your Weight and Health Risk.
- Adult nutrition & energy guidelines — USDA / HHS — Dietary Guidelines for Americans.
Last checked: April 2026. Rates and thresholds are reviewed against the source of record each November, when annual adjustments for the following tax year are published.