Educational tool — not a diagnosis. VivMetric calculators estimate body and fitness metrics using CDC, WHO, and NIH reference formulas. They do not provide medical advice, diagnosis, or treatment.
Always consult a licensed healthcare provider for medical concerns. If you are in emotional distress or thinking about harming yourself, contact the 988 Suicide & Crisis Lifeline (call or text 988, US, 24/7) or see the WHO mental-health resources.
Adult BMI Calculator — US Units (lb/in)
Instant Body Mass Index calculation with US imperial units by default. Enter your weight and height to see your WHO/CDC category update in real time.
How This Calculator Works
Type your weight in pounds and your height in inches into the fields above. The calculator recalculates instantly with every keystroke — there is no "Calculate" button. Your BMI value and category update in real time.
BMI Formula (US Imperial)
For imperial units, BMI is computed as:
BMI = 703 × weightlb / heightin²
The constant 703 converts pound-per-square-inch into the standard kilogram-per-square-meter scale used by WHO and CDC, so imperial and metric inputs yield numerically identical BMI values.
BMI Formula (Metric)
BMI = weightkg / heightm². If you enter centimeters, the calculator divides by 100 first.
CDC Adult BMI Classification & Health Risk
The CDC and WHO use the same four adult BMI categories, drawn from the WHO 2000 report Obesity: Preventing and Managing the Global Epidemic. The CDC further subdivides obesity into three classes for risk stratification. The table below lists every category, its BMI cut-point, and the population-level health risk the CDC associates with it.
| Category | BMI Range (kg/m²) | Health Risk (CDC) |
|---|---|---|
| Underweight | Below 18.5 | Increased risk of nutrient deficiencies, osteoporosis, and impaired immune function. |
| Normal weight | 18.5 – 24.9 | Lowest population-level risk for chronic disease; referent category. |
| Overweight | 25.0 – 29.9 | Moderately increased risk of type 2 diabetes, hypertension, and CVD. |
| Obese Class I | 30.0 – 34.9 | High risk of metabolic disease; weight-loss intervention typically recommended. |
| Obese Class II | 35.0 – 39.9 | Substantially increased risk; combined lifestyle and medical management. |
| Obese Class III | 40.0 and above | Very high risk (severe obesity); intensive intervention may be indicated. |
These cut-points apply to adults aged 20 and over. For ages 2–19, BMI is evaluated against CDC sex-specific percentile growth charts on our Teen BMI Calculator. All categories are screening labels, not clinical diagnoses — a healthcare provider must interpret BMI alongside body composition, fat distribution, and medical history.
Your healthy weight range
The calculator above shows the weight band that corresponds to a BMI between 18.5 and 24.9 at your entered height. For a 5 ft 9 in adult that range is roughly 125 to 168 lb. The CDC and NIH treat this band as a screening target, not a prescription. A modest 5 to 10 percent weight reduction for someone above the band is associated with measurable improvements in blood pressure, blood lipids, and fasting glucose. If you fall below the band, the priority shifts to preserving lean mass and nutrient intake rather than simply gaining weight.
What the CDC says about BMI limits
The CDC explicitly notes that BMI is a screening tool, not a diagnostic instrument. It does not distinguish lean mass from adipose tissue, and it does not measure body fat distribution. Two adults with the same BMI can have very different body compositions. The CDC also acknowledges that older adults may have a higher body fat percentage at the same BMI, and that very muscular individuals may be classified as overweight without excess fat. For a fuller picture, pair your BMI result with our Body Fat Calculator and Waist-to-Height Ratio tool.
BMI Chart for Adults (lb / in Lookup)
Use this BMI chart to look up your Body Mass Index without typing. Find your height (in feet/inches) on the left, then read across to your weight (in pounds). Each cell shows the BMI value color-coded by CDC category: underweight, normal, overweight, obese.
| Height | 100 lb | 120 lb | 140 lb | 160 lb | 180 lb | 200 lb | 220 lb | 240 lb |
|---|---|---|---|---|---|---|---|---|
| 4 ft 10 in (58 in) | 20.9 | 25.1 | 29.3 | 33.5 | 37.7 | 41.8 | 46.0 | 50.2 |
| 5 ft 0 in (60 in) | 19.5 | 23.4 | 27.3 | 31.2 | 35.2 | 39.1 | 43.0 | 46.9 |
| 5 ft 2 in (62 in) | 18.3 | 21.9 | 25.6 | 29.3 | 32.9 | 36.6 | 40.3 | 43.9 |
| 5 ft 4 in (64 in) | 17.2 | 20.6 | 24.0 | 27.5 | 30.9 | 34.3 | 37.8 | 41.2 |
| 5 ft 6 in (66 in) | 16.1 | 19.4 | 22.6 | 25.8 | 29.0 | 32.3 | 35.5 | 38.8 |
| 5 ft 8 in (68 in) | 15.2 | 18.3 | 21.3 | 24.3 | 27.4 | 30.5 | 33.5 | 36.6 |
| 5 ft 10 in (70 in) | 14.4 | 17.2 | 20.1 | 23.0 | 25.8 | 28.7 | 31.6 | 34.4 |
| 6 ft 0 in (72 in) | 13.6 | 16.3 | 19.0 | 21.7 | 24.4 | 27.1 | 29.9 | 32.6 |
| 6 ft 2 in (74 in) | 12.9 | 15.5 | 18.0 | 20.6 | 23.2 | 25.7 | 28.3 | 30.9 |
| 6 ft 4 in (76 in) | 12.2 | 14.7 | 17.1 | 19.5 | 22.0 | 24.4 | 26.9 | 29.3 |
BMI values in the table are rounded to one decimal place and computed with the CDC imperial formula BMI = 703 × lb / in². A BMI of 18.5 to 24.9 (green cells) is the CDC normal-weight band. To convert the chart to a personal target, find your height row and locate the weight columns that fall in the green band — that is your healthy weight range.
Interpreting Your BMI Result
BMI is a population-level screening ratio, not a diagnostic test. It is derived only from total weight and height and does not distinguish lean mass from adipose tissue. Two people with identical BMI values can have substantially different body compositions depending on muscularity, bone density, age, sex, and ethnicity. For individuals with high muscle mass, BMI may overestimate body fat. For older adults with reduced lean mass, BMI may underestimate adiposity. Always consult a qualified healthcare provider for medical concerns.
Once you know your BMI, the natural next step is to translate it into a calorie plan. Your BMR tells you how many calories you burn at rest, and your TDEE scales that by your activity level. Comparing the three numbers — BMI, BMR, and TDEE — gives you a much more complete picture than BMI alone.