Health and fitness
BMI Calculator
Your body mass index and which range you fall in
This BMI calculator divides your weight by your height squared and tells you which NHLBI category you fall in. It works in pounds and feet or in kilograms and centimeters. It is an estimate for adults, not a diagnosis.
An estimate for adults. It is not a diagnosis and does not replace advice from your doctor or another health professional.
The key idea
BMI is not a diagnosis: it is a first screen
The NHLBI puts a healthy weight at a BMI of 18.5 to 24.9 and obesity at 30 or above. But the index only uses weight and height: it cannot tell muscle from fat or where fat sits. A muscular athlete who is 5 ft 9 in and 180 lb gets 26.6, overweight on paper.
How it is calculated
BMI = weight (kg) / height (m)²
BMI = 703 × weight (lb) / height (in)²
NHLBI categories for adults: below 18.5, underweight; 18.5 to 24.9, healthy weight; 25.0 to 29.9, overweight; 30.0 or above, obesity.
BMI does not tell muscle from fat, so it can be misleading for athletes and older adults. It is not used the same way for children, teens or during pregnancy. If you have any doubt, talk to your doctor or a health professional.
Worked example
154 lb and 5 ft 9 in (69 in): 703 × 154 / 69² = 108,262 / 4,761 = 22.7 → healthy weight. The healthy range for that height is 125.3 to 168.6 lb.
Typical cases
BMI chart by height
The healthy weight range for adult heights and the BMI at 150 and 200 lb. It is an estimate: BMI does not tell muscle from fat.
| Height | Healthy weight range | BMI at 150 lb | BMI at 200 lb |
|---|---|---|---|
| 4 ft 10 in | 88.5 – 119.1 lb | 31.3 | 41.8 |
| 5 ft 0 in | 94.7 – 127.5 lb | 29.3 | 39.1 |
| 5 ft 2 in | 101.1 – 136.1 lb | 27.4 | 36.6 |
| 5 ft 4 in | 107.8 – 145.1 lb | 25.7 | 34.3 |
| 5 ft 6 in | 114.6 – 154.3 lb | 24.2 | 32.3 |
| 5 ft 8 in | 121.7 – 163.8 lb | 22.8 | 30.4 |
| 5 ft 10 in | 128.9 – 173.5 lb | 21.5 | 28.7 |
| 6 ft 0 in | 136.4 – 183.6 lb | 20.3 | 27.1 |
| 6 ft 2 in | 144.1 – 193.9 lb | 19.3 | 25.7 |
| 6 ft 4 in | 152.0 – 204.6 lb | 18.3 | 24.3 |
Save or share this table as an image Common questions
Frequently asked questions
What is BMI?
BMI is your weight in kilograms divided by your height in meters squared, or 703 times your weight in pounds divided by your height in inches squared. The NHLBI uses it to classify adult weight: below 18.5 is underweight, 18.5 to 24.9 is a healthy weight, 25.0 to 29.9 is overweight and 30.0 or above is obesity.
How is BMI different from body fat percentage?
BMI only relates weight to height, while body fat percentage estimates how much of your weight is fat. That is why a muscular person can have a high BMI with little fat. A health professional can measure your body composition if you need more detail.
What is a healthy weight for 5 ft 7 in?
About 118.1 to 159.0 lb, which matches a BMI of 18.5 to 24.9. It comes from multiplying those two values by your height squared and converting to pounds. The calculator shows this range for your own height.
Is BMI reliable?
It is reliable as a quick screen for large groups, but it is not enough to judge your health. It cannot tell fat from muscle, and it can mislead in older adults and very active people. Waist size and a check-up with a health professional fill in the picture.
Does BMI work for children and pregnant women?
No. Children and teens are assessed with BMI-for-age percentiles by sex, and during pregnancy weight changes for reasons BMI does not capture. In those cases, your pediatrician or your OB-GYN will give you the right reference.
What should I do if my BMI is outside the healthy range?
Treat it as a reason to talk to a health professional, not as a diagnosis. A BMI below 18.5 or of 30 or above is worth a medical check. If you want to change your weight, the calorie calculator gives you an estimate of what you need each day.
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