BMI Calculator
The BMI Calculator works out your Body Mass Index from your weight and height and tells you which standard category it falls into. Enter your weight and height to see your BMI number and whether it sits in the underweight, healthy, overweight or obese range.
What BMI measures
Body Mass Index is a simple screening number that relates your weight to your height. It does not measure body fat directly, but for most adults it gives a quick, useful indication of whether your weight is in a healthy range for your height. Health bodies worldwide use the same category boundaries.
The formula
BMI = weight (kg) ÷ height (m)2. In imperial units it is weight (lb) ÷ height (in)2 × 703. The result is a single number you compare against standard bands.
A worked example
Someone weighing 70 kg and 1.75 m tall has a BMI of 70 ÷ (1.75 × 1.75) = 70 ÷ 3.0625 = 22.9. That sits in the healthy range, which is generally 18.5 to 24.9. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is classed as obese.
What BMI does and does not tell you
BMI is a helpful starting point, not a full picture of health. Because it uses only weight and height, it can misclassify very muscular people as overweight and can miss excess fat in others. Use it as one signal alongside waist measurement, activity level and, where relevant, advice from a health professional.
How to use
- Enter your details in the fields above. The BMI Calculator accepts everyday values and checks them as you type.
- Press the action button (or just start typing for live tools) to run the calculation.
- Read your result, along with any supporting figures, in the clearly labelled result box.
- Use Copy result to grab the answer, Reset to start again, or Copy link to share this tool.
Why use this tool
Finance Wave built the BMI Calculator to be genuinely useful: it validates your input so you never see a broken result, formats numbers for your region automatically, and stays readable in both light and dark mode. Because everything happens on your device, it is private by design and keeps working even without an internet connection once the page has loaded.