BMI Calculator
Calculate adult Body Mass Index from height and weight, then review the standard BMI category and weight range for your height.
Calculate your BMI
Choose metric or US units. The sample values are real defaults, so Calculate works immediately.
Your BMI will appear hereCalculate to see BMI, adult category, formula and the standard weight range for your height.
Calculated BMI
Under 18.518.5–24.925–29.930+
BMI is a screening measure, not a diagnosis or a direct measurement of body fat. Muscle mass, pregnancy and other individual factors can affect interpretation.
What Your BMI Result Means
Body Mass Index compares weight with height using BMI = weight (kg) ÷ height² (m). For adults, standard BMI categories use the same numerical cutoffs for men and women. The calculator shows the category as a screening reference rather than treating BMI as a diagnosis.
The result also shows the weight range that corresponds to BMI 18.5–24.9 at the entered height. That range is a mathematical reference based on BMI alone, not an individualized target.
Adult BMI Categories
Below 18.5Underweight
18.5–24.9Healthy weight
25.0–29.9Overweight
30.0–34.9Obesity class 1
35.0–39.9Obesity class 2
40+Obesity class 3
BMI Formula and Example
For metric measurements, divide weight in kilograms by height in meters squared. For example, at 70 kg and 1.75 m:
BMI = 70 ÷ 1.75² = 22.86
Rounded to one decimal place, the BMI is 22.9, which falls within the standard adult 18.5–24.9 range.
When BMI Needs More Context
BMI does not distinguish muscle from fat and does not directly measure body composition or fat distribution. It can be less informative for some athletes, during pregnancy, and in other individual circumstances. For children and teenagers, BMI is interpreted using age- and sex-specific percentiles rather than the fixed adult categories used here.
Use BMI as a quick screening number and discuss health concerns or treatment decisions with a qualified healthcare professional.
Common Questions About BMI
How is BMI calculated?
BMI is calculated as weight in kilograms divided by height in meters squared. The calculator also accepts pounds plus feet and inches and converts them internally before applying the formula.
Does BMI use age or sex for adults?
The standard adult BMI formula uses height and weight only. Adult category cutoffs do not change by sex. Children and teens need age- and sex-specific BMI percentiles.
What does the weight range in the result mean?
It is the weight interval at the entered height that mathematically corresponds to BMI 18.5–24.9. It is a screening reference, not a personalized medical target.
BMI Calculator for Women
Adult BMI uses the same height-and-weight formula for women and men. Sex is not an input in the standard adult BMI equation. Pregnancy, muscle mass, age and individual medical circumstances can affect how a result should be interpreted.