BMI Calculator
Find out whether your weight fits your height. Enter two numbers and get your Body Mass Index, its category, and the healthy weight range for your height — instantly, with nothing uploaded anywhere.
BMI is a general screening guide for adults. It can overestimate body fat in athletes and underestimate it in older adults, and it is not used on its own to diagnose health conditions.
How to Calculate Your BMI
Three quick steps — no sign-up, no downloads.
1. Enter your details
Type your height and weight. Switch between metric (cm, kg) and US units (ft, in, lb) any time; age and gender are optional.
2. Press Calculate BMI
The maths runs in your browser the moment you click. Nothing is sent to a server.
3. Read your result
See your BMI score, which category it falls in, the healthy weight range for your height, plus your BMI Prime and Ponderal Index.
Why Use Our BMI Calculator?
Simple, fast, and completely private tools designed for everyday use.
Instant Result
Your BMI and category appear the moment you press calculate — no waiting, no page reloads.
Metric & US Units
Centimetres and kilos or feet, inches and pounds — use whichever system you think in.
More Than One Number
Alongside your BMI you get the healthy range for your height, your BMI Prime and your Ponderal Index for a fuller picture.
Private by Design
The calculation happens entirely on your device. Your height, weight and result are never uploaded or stored.
Common Questions About BMI
BMI (Body Mass Index) is a simple score that compares your weight with your height: weight in kilograms divided by height in metres squared. It gives a quick first indication of whether you are underweight, at a healthy weight, overweight, or obese.
For most adults, a BMI between 18.5 and 24.9 is considered the healthy range. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is obese.
BMI is a screening guide, not a diagnosis. It can read high for athletes with a lot of muscle and low for older adults, and different ranges apply to children and during pregnancy. For personal medical advice, always check with a doctor.
Both. Metric (centimetres and kilograms) is selected by default, and one tap switches to US units (feet, inches and pounds). Your result is identical either way.
No. This calculator runs entirely in your browser — your height, weight and result never leave your device and are not saved.
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Ready to try it?
Check your Body Mass Index and healthy weight range in seconds. 100% free and client-side private.