Body Mass Index

Know your number in seconds.

Enter your height and weight for an instant, visual read on where you fall. No account, no email, nothing saved.

ft in
lb
Your result will appear here once you enter height and weight.
15 18.5 25 30 40+

What BMI actually tells you

Body Mass Index estimates body fat using a simple ratio of weight to height. It was developed in the 1830s as a population-level statistic, not an individual diagnostic tool — which is why it's a starting point for a conversation about health, not the final word on it.

What it's good at

Flagging general weight-related risk trends across large groups. Doctors use it as one quick screening signal among many.

What it misses

Muscle mass, bone density, fat distribution, and body composition. A muscular athlete and a sedentary person can share the same BMI with very different health profiles.

How to use it

As one data point alongside waist circumference, activity levels, blood pressure, and how you actually feel — ideally discussed with a healthcare provider.

The four BMI categories

UnderweightBelow 18.5
Healthy weight18.5 – 24.9
Overweight25.0 – 29.9
Obesity30.0 and above