BMI calculator
Calculate body mass index from weight and height.
The BMI calculator takes your weight in kilograms and height in centimeters and computes your body mass index along with its general weight category (underweight, normal, overweight, or obese), using the standard formula and WHO category cutoffs.
How to use
- Enter your weight in kilograms and height in centimeters.
- Click "Calculate" to get your BMI and its general weight category.
Common use scenarios
- Getting a quick, general sense of your BMI from current weight and height.
- Tracking BMI over time alongside a fitness or health goal.
- Double-checking a BMI figure quoted from another source or app.
- Understanding which general weight category a BMI value falls into.
✓Content & verification reviewed: 2026-08-27
How we verify BMI calculator
How to confirm the result and understand its limits.
BMI = weight(kg) ÷ height(m)²
It's a simple ratio of weight to the square of height — a straightforward, widely used screening number, not a diagnostic measurement of body composition.
Category cutoffs follow the standard WHO ranges
Under 18.5 is underweight, 18.5–24.9 is normal, 25–29.9 is overweight, and 30+ is obese — these are general population screening thresholds, not personalized health targets.
BMI doesn't distinguish muscle from fat
A very muscular person can have a high BMI without carrying excess body fat, and BMI doesn't account for age, sex, or body frame — it's a starting point for a conversation with a healthcare professional, not a diagnosis.
Before you rely on the result
- You've entered weight in kilograms and height in centimeters, not other units.
- You understand BMI is a general screening number, not a full health assessment.
- You haven't used a high BMI reading alone to conclude something about body composition, especially if you're very muscular.
- You've consulted a healthcare professional for anything beyond a general reference point.
Who this is for
- Anyone wanting a quick, general sense of their BMI.
- People tracking BMI over time alongside a fitness or health goal.
- Anyone double-checking a BMI figure from another source.
- People wanting to understand what weight category a given BMI falls into.
Real-world examples
Quick BMI check
Someone enters their current weight and height to get a general BMI reading and category.
Tracking progress over time
A person recalculates their BMI periodically alongside a broader fitness routine to see the general trend.
Verifying a quoted BMI
Someone re-enters the numbers behind a BMI figure they saw elsewhere to confirm it was calculated correctly.
Limitations
- BMI is a simple weight-to-height ratio — it doesn't account for muscle mass, bone density, age, or sex, and isn't a diagnosis. Consult a healthcare professional for a proper health assessment.
Frequently asked questions
Is BMI an accurate measure of body fat?
Not directly — it's a weight-to-height ratio that doesn't distinguish muscle from fat, and doesn't account for age, sex, or frame. It's a general screening tool, not a body composition measurement.
Why might my BMI seem high even though I'm fit and muscular?
BMI can't tell the difference between muscle and fat by weight — a muscular person can have a higher BMI without excess body fat.
What units does this expect?
Weight in kilograms and height in centimeters. Convert your figures first if you have them in pounds or feet/inches.
Should I make health decisions based on this alone?
No — use it as a general reference point, and consult a healthcare professional for a proper, personalized health assessment.
🔒 Runs in your browser — nothing is uploaded. Results are for reference only; see the disclaimer. Last updated: 2026-08-27
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