BMI Calculator

A BMI calculator estimates a general weight category from height and weight, as a single number. It's widely used as a quick screening tool because it's fast to calculate, though it's a broad, population level measure rather than a precise read on any one person's health. It's worth treating as a starting point for a conversation, not a verdict on its own.

How to use it

1. Enter your height in centimeters.
2. Enter your weight in kilograms.
3. Read the calculated BMI.
4. Check the category badge underneath, underweight, healthy weight, overweight, or obese.
5. Adjust either value to see how the result changes.

When it helps

• Getting a general sense of where your weight falls relative to standard categories.
• Tracking BMI over time alongside other health measures.
• Preparing figures ahead of a doctor's appointment.
• Understanding the categories referenced in a health article or a fitness app.
• Comparing BMI figures across different units when reading international health guidance.

Good to know

• BMI doesn't tell the difference between muscle and fat, so a very muscular person can register as overweight despite low body fat.
• The categories come from population level data and might not fit every individual, age group, or ethnicity precisely.
• Use it as one data point among several, and talk to a doctor for a full picture rather than relying on BMI alone.
• If you're tracking BMI over time, note the date alongside each measurement somewhere, since a single number is far less useful than seeing the trend.
• If you're tracking fitness progress more broadly, pair a BMI reading with something like a waist measurement or how your clothes fit, since those add context a single number can't capture.

What BMI doesn't show

BMI doesn't separate muscle from fat or show where weight is carried, so it can mislead for athletes and older adults. Treat it as a screening figure and speak to a health professional about your own situation.

Questions