BMI Calculator
BMI, or Body Mass Index, is a simple numerical value calculated from your height and weight. It is widely used by healthcare professionals as a quick screening tool to identify potential weight-related health risks. This free BMI calculator gives you your result instantly in either metric or imperial units.
To calculate your BMI, enter your weight and height, select your preferred unit system, and click the button. Your BMI number will appear along with a classification: underweight, normal weight, overweight, or obese, based on the standard World Health Organization ranges.
Metric BMI formula: BMI = weight (kg) / height² (m)
Imperial BMI formula: BMI = (weight (lbs) / height² (inches)) × 703
It is important to note that BMI is a screening tool, not a diagnostic measure. It does not account for muscle mass, bone density, age, or fat distribution. Athletes, for example, may have a high BMI due to muscle while being perfectly healthy. Always consult a healthcare professional for a full health assessment.
This calculator works entirely in your browser. No data is sent to any server and nothing is stored. It is completely free and requires no account.
Frequently Asked Questions About BMI Calculator
Q: What is a healthy BMI range?
A: According to the WHO, a BMI between 18.5 and 24.9 is considered normal weight for adults. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is classified as obese.
Q: Is BMI accurate for everyone?
A: BMI is a general indicator. It may overestimate body fat in muscular people and underestimate it in older individuals who have lost muscle mass. It is best used alongside other health measurements.
Q: Can I use this calculator for children?
A: This calculator uses adult BMI ranges. For children and teenagers, BMI is interpreted differently using age and sex-specific charts. Consult a pediatrician for children's assessments.
Q: Does this BMI calculator store my data?
A: No. All calculations happen in your browser and no personal data is ever transmitted or stored.
Related tools: Age Calculator — Retirement Savings Calculator — Loan Repayment Calculator
For more on how age is calculated across different calendar systems, see this overview from Wikipedia.