About the Overweight Calculator
This calculator applies the standard Body Mass Index (BMI) formula to your weight and height, then compares the result to the adult weight categories published by the CDC and WHO. BMI is the most widely used screening measure for classifying weight status, precisely because it needs only two easy-to-measure inputs and produces a single, reproducible number.
The formula
BMI equals weight in kilograms divided by height in meters squared: BMI = kg ÷ m². In pounds and inches, the equivalent formula is BMI = 703 × weight(lb) ÷ height(in)² — the 703 constant converts pounds and inches into the metric ratio. This calculator accepts either unit system and does the conversion internally.
How to get accurate results
- Weigh yourself with minimal clothing, ideally in the morning before eating, for a consistent baseline — body weight can fluctuate 1–3 lb through the day.
- Measure height without shoes, standing straight against a flat wall.
- Double-check your unit selection — entering centimeters as inches (or vice versa) produces a BMI that is off by a large, obviously wrong margin.
Putting the result in context
The calculator reports your BMI, your CDC/WHO weight category, and — if your BMI is 25 or above — how much weight it would take to bring you down to a BMI of 24.9, the top of the normal range, along with that amount as a percentage of the target weight. These are population-based screening figures. BMI does not distinguish muscle mass from fat mass, so athletes and very muscular individuals can show a higher BMI without carrying excess body fat, and it does not account for age, sex, or fat distribution the way clinical body-composition tests do.
When to consult a professional
This calculator performs the standard BMI arithmetic for general screening and education. It is not a diagnosis of overweight or obesity and does not replace a clinical assessment. If your result concerns you, or if you are considering a weight-management plan, talk with a licensed healthcare provider who can weigh BMI alongside your health history and other measurements.