Body mass index
Weight and height in, BMI and weight category out. For adults 20 and older.
BMI chart for adults
The same BMI chart applies to men and women age 20 and older. The calculator above places your result on these ranges.
| BMI | Weight category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 to 24.9 | Healthy weight |
| 25.0 to 29.9 | Overweight |
| 30.0 to 34.9 | Class 1 obesity |
| 35.0 to 39.9 | Class 2 obesity |
| 40.0 or higher | Class 3 obesity (severe obesity) |
How to calculate BMI
Feet and inches go in together as total inches. A person who is 5 ft 9 in is 5 × 12 + 9 = 69 inches tall. The metric formula gives the same answer: 81.6 kg at 1.753 m is also a BMI of 26.6.
Want a number to aim for? The second tab turns a target BMI into a weight for your height. To see how many calories your body burns each day, try the BMR calculator.
Healthy weight by height
| Height | BMI 18.5 (lb) | BMI 24.9 (lb) |
|---|---|---|
| 5 ft 0 in | 95 | 127 |
| 5 ft 3 in | 104 | 141 |
| 5 ft 6 in | 115 | 154 |
| 5 ft 9 in | 125 | 169 |
| 6 ft 0 in | 136 | 184 |
| 6 ft 3 in | 148 | 199 |
For other formulas that estimate a single target number, see the ideal weight calculator.
What BMI does not show
BMI cannot tell muscle from fat. A lifter with a lot of muscle can land in the overweight range with little body fat, and a person who rarely exercises can have a healthy BMI and still carry extra fat around the waist.
- Some health groups use lower cutoffs for adults of Asian descent, because health risks can start at a lower BMI.
- Older adults often lose muscle, so the same BMI can hide more body fat.
- Pregnancy changes weight for good reasons, and BMI does not apply.
- For kids and teens (ages 2 to 19), the CDC compares BMI with growth charts by age and sex instead of using the adult chart.
For a closer look at composition, try the body fat calculator. Waist size and a checkup with your doctor add context that BMI leaves out.
Frequently asked questions
How do you calculate BMI?
Multiply your weight in pounds by 703, then divide by your height in inches squared. At 5 ft 9 in and 180 lb, the math is 703 × 180 ÷ 4,761 = 26.6. In metric, divide kilograms by meters squared.
What is a healthy BMI for my age?
For adults 20 and older, the healthy range is 18.5 to 24.9 at every age. The CDC uses one adult chart for men and women. Kids and teens are measured against growth charts by age and sex.
What BMI is considered obese?
A BMI of 30 or higher falls in the obesity range. The CDC splits it into class 1 (30 to 34.9), class 2 (35 to 39.9), and class 3 (40 or higher). BMI is a screening number, not a diagnosis.
Is BMI different for men and women?
No. The formula and the adult ranges are the same for both. Body composition differs between men and women, though, and BMI does not measure it.
What should I weigh for my height?
Use the weight range that matches a BMI of 18.5 to 24.9. At 5 ft 9 in, that is about 125 to 169 lb. The calculator shows the range for your exact height under the result.
Is BMI accurate for athletes?
Often not. Muscle weighs more than fat, so a muscular person can read as overweight without extra body fat. Waist size and body fat percentage give a better picture.
Sources and review
- Centers for Disease Control and Prevention (CDC): Adult BMI categories.
- World Health Organization: BMI classification for adults.