What is BMI?
Body Mass Index (BMI) compares your weight to your height. It is a quick screening tool doctors use to see if weight may be affecting health.
BMI categories for adults
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25 – 29.9 | Overweight |
| 30 and above | Obese |
The limits of BMI
BMI does not tell muscle from fat. Athletes can show as overweight while being lean, and older adults can show a normal BMI while carrying extra fat. For a closer look, measure your body fat percentage or your waist size. These categories are for adults 20 and older; children and teens use age-based percentiles.
How to use the BMI calculator
Enter your height in feet and inches (or cm) and your weight in pounds (or kg). Your BMI, category and healthy weight range for your height appear instantly. Sex and age don't change the BMI formula for adults, but they matter when you interpret it.
Example BMI calculation
A person who is 5 ft 9 in (69 inches) and weighs 180 lb has a BMI of 180 ÷ 69² × 703 = 26.6, which falls in the overweight range. The healthy BMI range for that height is about 125–168 lb.
BMI chart for common heights
| Height | Healthy weight (BMI 18.5–24.9) |
|---|---|
| 5 ft 0 in | 95–127 lb |
| 5 ft 3 in | 104–141 lb |
| 5 ft 6 in | 115–154 lb |
| 5 ft 9 in | 125–168 lb |
| 6 ft 0 in | 136–184 lb |
| 6 ft 3 in | 148–199 lb |
Go beyond BMI
BMI is a screening tool. Add your waist size (keep it under half your height) and your body fat percentage for a clearer picture. Our guide BMI vs body fat percentage explains when each one is more useful. To see a target weight, try the ideal weight calculator.
Frequently asked questions
What is a healthy BMI?
For adults, a BMI from 18.5 to 24.9 is considered a healthy weight range.
Is BMI different for men and women?
The formula and categories are the same for adult men and women, although women usually carry more body fat at the same BMI.
What is BMI Prime?
BMI Prime is your BMI divided by 25, the top of the healthy range. A value under 1.0 means you are at or below the upper healthy limit.
Is BMI accurate for muscular people?
Not very. BMI can overestimate fat in people with a lot of muscle. Body fat percentage is a better measure for them.
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