BMI Calculator
Calculate your Body Mass Index quickly and easily using US or metric units. Get your BMI value, weight category, healthy BMI range, and useful results in seconds.
Calculate Your BMI in Seconds
Select your preferred measurement system and enter your information below.
Understanding Your BMI Result
For adults 20 and older, BMI is grouped into standard weight categories. Use these ranges as a screening guide, not as a diagnosis.
| BMI Category | BMI Range |
|---|---|
| Underweight | Below 18.5 |
| Healthy Weight | 18.5 to less than 25 |
| Overweight | 25 to less than 30 |
| Obesity Class 1 | 30 to less than 35 |
| Obesity Class 2 | 35 to less than 40 |
| Obesity Class 3 | 40 or greater |
What Your BMI Can Tell You
BMI is a simple measurement that compares body weight with height. It can provide a useful starting point when looking at weight status.
Weight Status
Your BMI can place your result into an adult weight category such as healthy weight, overweight, or obesity.
Healthy Range
For adults, a BMI from 18.5 to less than 25 is generally classified as the healthy weight range.
Quick Screening
BMI can be useful for screening, but it should be considered alongside other health information.
Easy Calculation
Enter your height and weight once to instantly calculate your BMI without doing the math manually.
How BMI Is Calculated
BMI, or Body Mass Index, is a measurement calculated from a person's weight and height. It provides a simple way to estimate weight status and is commonly used as a screening measure for adults.
Metric BMI Formula
With metric measurements, BMI is calculated by dividing weight in kilograms by height in meters squared.
BMI = weight (kg) ÷ height² (m)
US BMI Formula
With US customary measurements, BMI is calculated using weight in pounds and height in inches.
BMI = 703 × weight (lb) ÷ height² (in)
Is BMI the Same for Everyone?
Adult BMI categories are generally applied to people 20 years and older. BMI does not directly measure body fat and does not account for every factor that can affect health.
For children and teenagers ages 2 through 19, BMI is interpreted differently using age- and sex-specific BMI-for-age percentiles. This calculator is designed for adults.
BMI Is a Screening Measure
A BMI result should not be treated as a diagnosis. Factors such as muscle mass, medical history, physical activity, and other health indicators may also be important when evaluating overall health.
Learn More About Body Mass Index (BMI)
Body Mass Index (BMI) is a screening measure that compares weight with height. Although BMI can help assess weight categories, it does not directly measure body fat and should be considered alongside other health factors. Learn more in the CDC's guide to Body Mass Index .
Simple BMI Calculation Examples
These examples show how height and weight work together when calculating Body Mass Index.
Example 1
A person who weighs 70 kg and is 1.75 m tall has a BMI of approximately 22.9.
Example 2
A person who weighs 90 kg and is 1.80 m tall has a BMI of approximately 27.8.
Example 3
A person who weighs 100 kg and is 1.70 m tall has a BMI of approximately 34.6.
A Simple Way to Check Your BMI
DoMorely makes everyday calculations easier with clean, fast, and straightforward online tools.
Fast Results
Calculate your BMI instantly without manually applying the formula.
Two Unit Systems
Switch easily between US Units and Metric Units based on the measurements you use.
Useful Results
See BMI category, healthy BMI range, BMI Prime, Ponderal Index, and estimated healthy weight range.
Mobile Friendly
The calculator adapts to smaller screens for a comfortable experience on phones and tablets.
Frequently Asked Questions
Find quick answers to common questions about BMI and using this calculator.
What is BMI?
BMI stands for Body Mass Index. It is a calculated measurement based on weight and height that is used as a screening measure for weight status.
What is a healthy BMI?
For adults 20 years and older, a BMI from 18.5 to less than 25 is classified as the healthy weight range.
Can BMI diagnose a health condition?
No. BMI is a screening measure and should not be used by itself to diagnose disease or determine overall health.
Is this BMI calculator for children?
This calculator is designed for adults. Children and teenagers ages 2 through 19 should have BMI interpreted using age- and sex-specific BMI-for-age percentiles.
What is BMI Prime?
BMI Prime is your BMI divided by 25. It provides a simple comparison against the upper boundary of the standard healthy BMI range.
Can I use US and metric measurements?
Yes. Select US Units when entering height in feet and inches and weight in pounds. Select Metric Units when entering height in centimeters and weight in kilograms.
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