BMI Calculator
Health
Body Mass Index calculator
Enter your weight and height to compute your BMI, see which category you fall into, and understand what the number means.
BMI Calculator
Enter your weight and height to calculate body mass index (BMI).
Result
Your BMI and category for adults.
About BMI
BMI is a simple screening measure for adults. It does not measure body fat directly, and may misclassify muscular individuals. For medical advice, consult a professional.
What this calculator does
The BMI Calculator takes your weight and height, applies the standard Body Mass Index formula, and returns a numeric score along with a visual gauge showing your category. BMI is a widely used screening tool that helps indicate whether a person may be underweight, at a healthy weight, overweight, or obese based on population-level data.
Who should use this calculator
Anyone looking for a quick health screening reference — fitness enthusiasts tracking progress, individuals starting a weight-management programme, parents checking guidelines, or professionals in nutrition and wellness who need a rapid calculation. BMI is not a diagnostic tool on its own, so use it alongside other health metrics for a fuller picture.
How BMI is calculated
BMI is calculated using the formula: BMI = weight (kg) ÷ height (m)². If you enter values in pounds and inches, the calculator converts them before applying the formula. The result is a dimensionless number that maps to standard categories defined by the World Health Organization: underweight (below 18.5), normal weight (18.5–24.9), overweight (25–29.9), and obese (30 and above).
How to interpret your result
A BMI in the 18.5–24.9 range is generally associated with lower risk of weight-related health issues. Values outside this range suggest it is worth discussing lifestyle, nutrition, or further assessment with a healthcare professional. Remember that BMI is a population-level indicator — it does not measure body fat directly and may not capture individual variations such as muscle mass, bone density, or fat distribution.
Example
A person who weighs 70 kg and is 1.75 m tall has a BMI of 70 ÷ (1.75 × 1.75) = 22.9, which falls in the normal-weight category. A person weighing 95 kg at the same height has a BMI of 31.0, placing them in the obese category. Try entering your own values to see where you stand.
BMI categories at a glance
| Category | BMI range |
|---|---|
| Underweight | Below 18.5 |
| Normal weight | 18.5 – 24.9 |
| Overweight | 25.0 – 29.9 |
| Obese | 30.0 and above |
Limitations & disclaimer
BMI does not differentiate between lean mass and fat mass, does not account for age, sex, ethnicity, or body-fat distribution, and should not be used as a sole diagnostic measure. Individuals with high muscle mass, pregnant women, and the elderly may receive misleading classifications. This calculator is for informational purposes only — consult a healthcare professional for personalised health assessments.
Frequently asked questions
Is BMI accurate for athletes or muscular people?
BMI does not distinguish between muscle and fat mass. Athletes with high muscle mass may be classified as overweight despite having low body fat. Use BMI as a starting point and consider additional measures such as waist circumference or body-fat percentage.
Does BMI apply the same way to all age groups?
Standard BMI categories are designed for adults aged 20 and older. For children and teenagers, BMI is interpreted using age- and sex-specific percentile charts. Consult a paediatrician for child-specific guidance.
What BMI range is considered healthy?
The World Health Organization classifies a BMI of 18.5 to 24.9 as normal weight. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is classified as obese. These thresholds may differ slightly for certain ethnic groups.
How often should I check my BMI?
BMI changes with weight and height fluctuations. Checking once every few months is sufficient for general health tracking. Significant or rapid changes warrant a conversation with a healthcare provider.
Does this calculator store my data?
No. All calculations run entirely in your browser. Your weight and height inputs are never sent to our servers or stored anywhere.