 Online Calculators

## Calculator Use

This calculator will determine Body Mass Index or BMI, given an individual's weight and height. Weight can be entered pounds, stones and pounds, or kilograms. Height can be entered in inches, feet and inches, meters, or centimeters.

This calculator will also calculate and display the normal weight range for the height entered.

## Calculating BMI

BMI is a way of measuring a person's weight relative to his or her height. BMI expresses how thick or thin a person is in simple numeric terms, and allows doctors and other health professionals to discuss weight objectively on a standardized scale.

## BMI Formulas

This BMI calculator converts units to satisfy the following BMI formula calculations.

• Metric units: BMI = weight (kg) ÷ height2 (m)
• US units: BMI = (weight (lb) ÷ height2 (in)) * 703

### Normal Weight Range

Normal weight BMI is 18.5 to 24.9. To calculate your normal weight range use the following:

• Metric units:
minimum weight (kg) = 18.5 × height2 (m)
maximum weight (kg) = 24.9 × height2 (m)
• US units:
minimum weight (lb) = (18.5 ÷ 703) × height2 (in)
maximum weight (lb) = (24.9 ÷ 703) × height2 (in)

### Example 1 (Calculating BMI in metric units)

Matilda weighs 64 kg and is 1.9 meters tall. What is her BMI?

• BMI = w ÷ h2
• BMI = 64 ÷ 1.92
• BMI = 64 ÷ 3.61
• BMI = 17.7

### Example 2 (Calculating BMI in US units)

Stanley weighs 184 lb and is 5 feet, 10 inches tall. What is his BMI?

• 5 feet, 10 inches = 70 inches
• BMI = (w ÷ h2) * 703
• BMI = (184 ÷ 702) * 703
• BMI = (184 ÷ 4900) * 703
• BMI = 0.3755 * 703
• BMI = 26.4

Below is a table of commonly used BMI ranges in North America and Europe for persons aged 21 and older. Wikipedia lists more detailed BMI categories.

BMI Ranges
BMI
Category
< 16.0
Severely Underweight
16.0 - 18.4
Underweight
18.5 - 24.9
Normal
25.0 - 29.9
Overweight
30.0 - 34.9
Moderately Obese
35.0 - 39.9
Severely Obese
> 40.0
Morbidly Obese

Although BMI is calculated the same way worldwide for all ages, the way an individual's BMI is interpreted depending on location and the person's age:

• In many Southeast Asian countries, the thresholds for the overweight and obese categories tend to be lower. For example, in Singapore and Hong Kong a BMI of 23.0 is considered overweight, whereas in the United States a BMI of 25 is considered overweight.
• Children and adolescents are not evaluated using these thresholds at all, but are evaluated relative to others of the same age and gender:

Keep in mind that BMI is a ratio between height and total body weight - it does not differentiate between weight from muscle and weight from fat, nor does it consider an individual's body frame type. BMI is one of several tools used to assess a person's weight and overall health. If you are concerned about your weight, it is best to consult with your doctor or healthcare professional.

## References

Cite this content, page or calculator as:

Furey, Edward "BMI Calculator (Body Mass Index)" at https://www.calculatorsoup.com/calculators/health/bmi-calculator.php from CalculatorSoup, https://www.calculatorsoup.com - Online Calculators