Understanding Your BMI: What the Number Really Means
Body Mass Index (BMI) is a quick screening number that relates your weight to your height. It's not a diagnosis, but it's a useful starting point for a conversation about health.
Here's how BMI works, what the ranges mean, and why it's only part of the picture.
The formula
BMI = weight (kg) ÷ height (m)². For example, 70 kg at 1.75 m gives 70 / 3.06 = 22.9.
What the ranges mean
Below 18.5 is underweight, 18.5–24.9 is the healthy range, 25–29.9 is overweight, and 30+ is in the obese category. These are screening bands, not verdicts.
Limitations
BMI doesn't distinguish muscle from fat, so athletes can read high. Pair it with body fat percentage and waist-to-hip ratio for a fuller view.
Related calculators
Frequently asked questions
Is BMI accurate for athletes?
Not always — high muscle mass can push BMI into the overweight range despite low body fat.
What's a healthy BMI?
For most adults, 18.5–24.9 is considered the healthy range.
This tool provides educational information and is not intended to replace professional medical advice.