Body mass index, or BMI, is a quick screening number that compares your weight with your height. It is not a full picture of health, but it is a useful starting point. Enter your height and weight below to see your BMI, your category, and the healthy weight range for your height.

BMI Calculator

How BMI Is Calculated

BMI uses a simple formula: BMI = 703 x weight (lb) / height (in) squared. The result is sorted into categories used by the CDC and the World Health Organization for adults 20 and older.

BMI Category
Below 18.5 Underweight
18.5-24.9 Healthy weight
25.0-29.9 Overweight
30.0 and above Obesity

Healthy Weight Range by Height

Height Healthy Weight Range
5’0″ 95-127 lb
5’4″ 108-145 lb
5’8″ 122-164 lb
6’0″ 136-184 lb
6’4″ 152-205 lb

What BMI Does Not Tell You

BMI cannot tell the difference between muscle and fat, and it says nothing about where fat is stored. Muscular athletes often land in the overweight range despite low body fat, while some people with a healthy BMI carry more body fat than is ideal. BMI categories are also less precise for older adults and for some ethnic groups. For children and teens, a different, age-specific chart is used.

That is why it helps to look at BMI alongside other measures such as waist circumference, body fat percentage, resting heart rate, and daily activity, many of which your wearable already tracks.

Beyond the Number

If your BMI is outside the healthy range, small daily changes add up. Knowing your TDEE gives you a realistic calorie target, and a step goal on your tracker is an easy way to build more movement into your day without a big schedule change.

Disclaimer: BMI is a screening tool, not a diagnosis. It is not medical advice. Talk with a healthcare provider before making major changes to your exercise, diet, or sleep, especially if you have a health condition or take medication.