BMI Calculator - Body Mass Index for Adults
Calculate Body Mass Index (BMI) using metric or imperial measurements with visual category scale and healthy weight guidance.
How to use BMI Calculator in 3 simple steps
Choose Measurement Unit
Select Metric (cm and kg) or Imperial (feet, inches, and pounds).
Enter Height and Weight
Input your height and weight values.
Review BMI Category
See your calculated BMI score, health category indicator bar, and standard healthy weight range.
Something not working?
Found a bug in BMI Calculator or have an idea that would make it better? Email me directly and I'll take a look.
Email me directly coderbt66@gmail.comNo account and no uploads — your message is sent through your own email app.
Understanding Body Mass Index and Healthy Weight Ranges
Body Mass Index (BMI) is an international screening metric established by the World Health Organization (WHO) to categorize body mass based on height and weight. It provides a simple benchmark to identify whether an adult falls into underweight, normal weight, overweight, or obese ranges.
Toolnova BMI Calculator accepts both metric units (centimeters and kilograms) and imperial units (feet, inches, and pounds). As you input your metrics, it plots your score along a clear color-coded scale and estimates your recommended healthy weight range according to WHO guidelines.
Please note: BMI is an informative general health screening tool, not a diagnostic medical evaluation. It does not measure body fat percentage directly or differentiate between muscle mass and adipose tissue.
Key features & capabilities
Frequently asked questions about BMI Calculator
Common questions about usage, privacy, limits, and browser compatibility.
What is the BMI formula?
In metric units, BMI is weight in kilograms divided by height in meters squared. In imperial units, it is weight in pounds divided by height in inches squared, multiplied by 703. The calculator applies the correct version for the units you select.
What are the WHO BMI categories?
The World Health Organization adult ranges are under 18.5 for underweight, 18.5 to 24.9 for normal weight, 25 to 29.9 for overweight, and 30 or above for obese. The tool plots your score on a color-coded scale against these bands. These cutoffs apply to adults, not children.
Is BMI accurate for athletes?
BMI can overestimate body fat in athletes and bodybuilders because muscle is denser than fat and adds weight without adding fat. Someone with high muscle mass may land in the overweight category despite low body fat. BMI is a screening measure, so pair it with other assessments rather than relying on it alone.
Does BMI work the same way for children?
The calculator uses WHO adult categories, so it is intended for adults rather than children or teenagers. For people under 18, doctors typically use age- and sex-specific BMI percentiles instead of fixed cutoffs. Ask a pediatric professional if you need a child's measurement interpreted.
How is my healthy weight range calculated?
The range is derived from the BMI values of 18.5 to 24.9 applied to your height. In metric terms, the lower bound is 18.5 times your height in meters squared, and the upper bound is 24.9 times the same figure. It is a broad reference band, not a personal target.
Is BMI a medical diagnosis?
BMI is a general screening indicator, not a diagnosis, and it does not measure body fat directly. A clinician may combine it with waist measurements, medical history, and other tests before drawing conclusions. Use the result as a starting point for a conversation, not as medical advice.