Calculate your Body Mass Index instantly, with category classification and healthy weight range — in metric or imperial units.
A BMI between 18.5 and 24.9 is generally considered healthy for most adults, per WHO classification.
BMI is a useful screening tool but doesn't account for muscle mass or body composition, so it may be less accurate for athletes, elderly people, or pregnant women.
BMI = weight in kg ÷ (height in meters)². For imperial units, BMI = 703 × weight in lb ÷ (height in inches)².
It shows the weight range that would give you a BMI between 18.5 and 24.9, based on your entered height.
Body Mass Index (BMI) is a widely used screening measure that estimates whether a person's weight is healthy relative to their height. This calculator computes your BMI instantly in either metric (kilograms and centimeters) or imperial (pounds and feet/inches) units, and shows which of the four standard WHO categories your result falls into: underweight, normal weight, overweight, or obese.
In metric units, BMI is calculated as weight in kilograms divided by height in meters squared (kg/m²). In imperial units, the formula is adjusted with a conversion factor: 703 × weight in pounds, divided by height in inches squared. Both formulas produce the same BMI value for the same person — they're just different ways of expressing the same underlying weight-to-height-squared ratio.
BMI is a useful, quick screening tool precisely because it only requires height and weight, but it doesn't distinguish between muscle mass and fat mass. A muscular athlete can have a "high" BMI while carrying very little body fat, while someone with low muscle mass and high body fat could have a "normal" BMI despite carrying unhealthy levels of fat. BMI also doesn't account for fat distribution, age-related changes, or differences between individuals of different body frames. It's best used as a general population-level screening indicator rather than a definitive individual health diagnosis — a doctor or health professional can provide more complete context using additional measurements.
Alongside your BMI number, this tool calculates the weight range that would put you in the "normal" BMI category (18.5–24.9) at your current height. This can be a more actionable number than the BMI value itself, since it translates the BMI formula back into a concrete weight target in your usual units.
All calculations happen directly in your browser using JavaScript — your height and weight are never sent to a server or stored anywhere.