Adult BMI Metric Calculator
Calculate adult body mass index from kilograms and centimeters. BMI is a screening measure and does not by itself describe an individual's health.
Where your BMI falls
Your result is in the adult healthy weight screening category. The height-based weight range is an estimate, not a personal target. The tri-ponderal index uses cubed height; the BMI categories do not apply to it. Values outside 10–40 appear at the nearest end of the scale. BMI alone cannot diagnose health. CDC categories.
About this calculation
Body mass index (BMI) relates weight to height with one number. This tool is for adults aged 20 and older and reports BMI in kg/m². It can help start a conversation about weight status, but it does not diagnose health or measure body fat directly. Enter kilograms and centimeters in the fields below.
Formula
BMI = weight(kg)/height(m)²
Worked example
With Weight: 75 kg, Height: 175 cm, bmi is 24.489796 kg/m².
What BMI measures
The metric BMI equation divides kilograms by meters of height squared. For example, a 5 cm height-entry error changes the denominator after conversion to meters, so check that the centimeter field contains your full height. At equal weight, a taller person has a smaller calculated BMI because the squared height is larger.
Enter weight in kilograms and height in centimeters. The calculator converts centimeters to meters, squares the height in meters, then divides kilograms by that squared height.
Adult BMI ranges
For adults aged 20 and older, CDC screening categories apply to the BMI produced from kilograms and meters. Category boundaries include their lower value: a computed 25.0 belongs to the overweight range. The ranges describe BMI numbers, not a prescribed kilogram value for every person.
- Underweight: below 18.5
- Healthy weight: 18.5 to below 25
- Overweight: 25 to below 30
- Obesity, class 1: 30 to below 35
- Obesity, class 2: 35 to below 40
- Obesity, class 3: 40 or higher
Worked example
An adult weighing 70 kg at 1.75 m has BMI = 70 ÷ (1.75 × 1.75) = 22.86 kg/m². That falls in the adult healthy-weight range. A different height or weight changes the number; the category is an interpretation of the number, not a medical conclusion.
How to interpret your result
Read the BMI and its adult screening category together, then consider waist measurement, health history, activity, and clinical findings. Kilograms divided by height squared do not reveal what share of body mass is muscle or where fat is distributed. People with different body compositions can therefore have the same BMI.
The adult metric tool does not ask for age or sex because CDC adult cutoffs use the same numeric boundaries after age 20. For someone aged 2–19, use a child and teen BMI-for-age tool rather than this kilogram-and-centimeter adult chart; the reference depends on age and sex.
What the extra numbers mean
The displayed weight interval multiplies your height in meters squared by 18.5 and by 25. It is the kilogram interval corresponding arithmetically to the CDC adult healthy-weight BMI range at that exact entered height. The upper endpoint is excluded because BMI 25 starts another category. It is not a personal weight goal.
BMI Prime is this BMI divided by 25, so 1.00 lines up with the adult category boundary. The tri-ponderal index divides your kilograms by height in meters cubed and reports kg/m³. It uses a different power of height, has no CDC adult BMI categories, and is presented only as a comparison of mathematical indices.
Measurement and scope
Measure standing height in centimeters without shoes and use a recent kilogram weight. A small change in height has a squared effect in the BMI formula, which matters most near a category boundary. Pregnancy, unusually high muscle mass, or medical conditions may complicate interpretation. Discuss individual concerns with a qualified health professional.
Common questions
Is BMI a measure of body fat?
No. The metric inputs describe mass and height, not muscle, fat, or the distribution of tissue.
Does the same BMI range apply to children?
No. The adult kilogram-and-centimeter chart cannot replace BMI-for-age percentiles for ages 2–19.
What does a BMI of 25 mean?
For an adult, 25.0 is the beginning of the overweight screening category; it is not a clinical diagnosis.
Is the weight interval a recommended target?
No. It only applies adult BMI boundaries to the entered height and expresses the result in kilograms.
Can I share my calculation?
Yes. A share link contains the kilograms and centimeters you entered, so anyone with that link can read them.
Sources and references
Inputs
- Weight (kg)
- Height (cm)