BMI Calculator
The BMI Calculator helps you determine your Body Mass Index — a widely used screening tool to assess whether you have a healthy body weight for your height. Simply enter your height and weight to get instant results.
Educational estimate. Calculator results are for planning and information only, not financial, tax, medical, legal, or engineering advice. Verify important decisions with official sources or a qualified professional.
BMI Calculator
Calculate Your Body Mass Index
📐 Formula & Method
BMI Formula (Metric)
Divide your weight in kilograms by the square of your height in meters.
BMI Formula (Imperial)
Divide your weight in pounds by the square of your height in inches, then multiply by 703.
📋 How to Use
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1
Select your preferred unit system (Metric or Imperial).
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2
Enter your current weight in kg (or lbs for imperial).
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3
Enter your height in cm (or feet/inches for imperial).
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4
Click "Calculate" to see your BMI score and category.
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5
Review the BMI category table to understand your result.
What is BMI and Why Does It Matter?
Body Mass Index (BMI) is a numerical value calculated from a person's weight and height. It is a widely used screening tool to identify potential weight-related health issues. BMI was developed by Belgian mathematician Adolphe Quetelet in the 1830s and has since become one of the most commonly used health indicators worldwide.
While BMI is a useful population-level screening tool, it is not a diagnostic measure. It does not directly measure body fat, muscle mass, or fat distribution. However, research has shown that BMI correlates with direct measures of body fat, such as underwater weighing and dual-energy X-ray absorptiometry (DXA).
Adults with a BMI between 18.5 and 24.9 are considered to have a normal or healthy weight. A BMI below 18.5 indicates underweight, 25.0 to 29.9 indicates overweight, and a BMI of 30 or above indicates obesity. For children and teens, BMI is interpreted using age and sex-specific percentiles.
If your BMI falls outside the normal range, it is recommended to consult a healthcare professional for a more comprehensive health assessment. Lifestyle changes including balanced nutrition and regular physical activity can help achieve and maintain a healthy BMI.
🔬 Methodology & Accuracy
Formula: Uses the standard mathematical formula shown in the Formula & Method section above. All computations run client-side in your browser — no data is sent to our servers.
Data sources: Tax bands, contribution limits and regulatory rates are taken from official US (IRS, SSA) and UK (HMRC, gov.uk) publications for the current tax year, and updated when bands change.
Last reviewed: June 2026 · Accuracy: Results are precise to two decimal places using IEEE-754 double-precision arithmetic. Intended for educational and planning use only.
For informational purposes only. Results are estimates based on the inputs and formulas provided. For financial, tax, medical, or legal decisions, consult a qualified professional. Rates and regulations change — always verify current figures with official sources.