BMI Calculator

How It Works

BMI (Body Mass Index) is a simple screening tool that uses your height and weight to estimate whether you fall into a healthy weight range. It is calculated as:

For imperial units (like we use here), the formula is:

What the Categories Mean

• Underweight (<18.5): May indicate malnutrition or other health issues. Consult a healthcare provider.
• Normal (18.5–24.9): Associated with the lowest health risk for most adults.
• Overweight (25–29.9): May indicate increased risk for cardiovascular conditions. Lifestyle changes are often recommended.
• Obese (≥30): Associated with significantly higher risk for diabetes, heart disease, and certain cancers. Medical guidance is advised.

Limitations

BMI does not distinguish between muscle and fat. Athletes with high muscle mass may register as "overweight" despite low body fat. Similarly, older adults may have normal BMI but high body fat percentage. For a more complete picture, use our Body Fat Estimator or Waist-to-Height Ratio tools alongside this calculator.

Practical Tips

• Weigh yourself at the same time each day (preferably morning, after using the bathroom, before eating).
• Use a digital scale on a hard, flat surface for consistency.
• Track trends over weeks, not day-to-day fluctuations. The 7-day moving average in this tool smooths out water-weight noise.
• Your data is saved in your browser's localStorage. Clear it anytime by clicking "Clear History."