BMI Calculator
Enter your height and weight in centimetres and kilograms or feet, inches and pounds to get your BMI. The result shows your adult WHO category on a colour scale, the weight range that corresponds to a healthy BMI for your height and how far you are from it. The limitations of BMI are explained alongside so you can read the number in context.
How to use the BMI Calculator
- Choose metric or imperial units.
- Enter your height and weight.
- Press Calculate BMI.
- Read your BMI, WHO category and healthy weight range for your height.
Features
- Metric (cm, kg) and imperial (ft, in, lb) input
- WHO adult categories including obesity classes I–III
- Healthy weight range for your height (BMI 18.5–24.9)
- Visual scale showing where your BMI falls
Benefits
- A quick, private screening check you can repeat over time
- Turns a BMI number into a practical weight range
- Clear notes on when BMI is misleading
Frequently asked questions
How is BMI calculated?
BMI = weight in kilograms ÷ (height in metres)². For imperial units the calculator converts to metric first, which gives the same result as the 703 × lb ÷ in² formula.
What are the WHO BMI categories?
Below 18.5 is underweight, 18.5–24.9 is healthy, 25–29.9 is overweight, and 30 or above is obesity (class I 30–34.9, class II 35–39.9, class III 40+).
Who should not rely on BMI?
BMI is not suitable for children and teenagers (who need age- and sex-specific percentiles), during pregnancy, or for very muscular people. Some ethnic groups have higher risk at lower BMIs.
Is my BMI result medical advice?
No. BMI is an estimate and a screening tool, not a diagnosis. Speak to a doctor or other health professional about your health and weight.
Related tools
- BMR & Calorie Calculator — Estimate your BMR with the Mifflin-St Jeor equation, your maintenance calories by activity level, and daily targets to lose or gain weight.
- Ideal Weight Calculator — Estimate ideal body weight from your height and sex with the Devine, Robinson, Miller and Hamwi formulas, in kilograms and pounds.
- Percentage Calculator — Work out X% of Y, what percent one number is of another, percentage change, or increase and decrease a value by a percent.
- Loan EMI Calculator — Calculate the monthly EMI for any loan, plus total interest, total payment and a year-by-year repayment breakdown.
- Invoice Generator — Create a professional invoice with your details, line items, discounts, tax and shipping, then download it as a PDF or print it.
- Word Counter — Count words, characters, sentences and paragraphs live, with reading time and top keywords.