BMI Calculator
Check your Body Mass Index & weight category.
100% private — runs in your browser, nothing is uploaded.
Enter your height and weight to calculate your BMI.
| BMI range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obese |
How to use the BMI Calculator
- 1Choose your units
Pick Metric (cm, kg) or Imperial (ft, in, lb) using the toggle.
- 2Enter your height
Type your height in the height field(s) for the chosen unit system.
- 3Enter your weight
Add your current weight and the BMI updates instantly.
- 4Read your category
See your BMI number and which weight category it falls into, using the reference table below.
Examples
| Input | Output |
|---|---|
170 cm, 65 kg | BMI 22.5 — Normal weight |
5 ft 9 in, 200 lb | BMI 29.5 — Overweight |
Free online BMI calculator
This BMI calculator works out your Body Mass Index from your height and weight and tells you which category you fall into — underweight, normal, overweight or obese. It supports both metric and imperial units.
What BMI tells you
Body Mass Index is a quick way to check whether your weight is in a healthy range for your height. It is widely used by doctors and health organisations as an initial screening measure. Remember that BMI does not account for muscle mass, so very muscular people may read as “overweight” despite low body fat.
The BMI formula
- Metric: BMI = weight (kg) ÷ height (m)².
- Imperial: BMI = 703 × weight (lb) ÷ height (in)².
This calculator runs entirely in your browser, so your measurements stay private and it works even without an internet connection. It is intended for general information and is not a substitute for professional medical advice.
Frequently Asked Questions
How is BMI calculated?
BMI equals your weight in kilograms divided by your height in metres squared (kg ÷ m²). If you use imperial units, the tool converts feet, inches and pounds to metric first.
What is a healthy BMI range?
For most adults, a BMI between 18.5 and 24.9 is considered normal. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is classified as obese.
Is BMI accurate for everyone?
BMI is a useful general screening tool but it does not distinguish muscle from fat. Athletes, older adults, pregnant people and children may need different measures. Treat it as a guide, not a diagnosis.
Does BMI work the same for men and women?
The BMI formula and adult categories are the same for men and women. Body composition differs between individuals, so BMI is best used alongside other health indicators.
Can I use pounds and feet instead of kilograms?
Yes. Switch the toggle to Imperial to enter your height in feet and inches and your weight in pounds — the calculator handles the conversion automatically.
Is my height and weight data private?
Completely. The calculation happens in your browser and nothing is uploaded or stored, so your measurements never leave your device.