1. What is BMI?

Body Mass Index (BMI) is a simple calculation using a person's height and weight. It provides a reliable indicator of body fatness for most people and is used to screen for weight categories that may lead to health problems.

2. How BMI is Calculated

The BMI formula is:

Where:

• \( weight \) — Body weight in kilograms
• \( height \) — Height in meters

Explanation: BMI correlates fairly well with body fat percentage for most people, though athletes with high muscle mass may have higher BMI without excess fat.

3. BMI Categories for Females

Details: For adult females (age 20+):

• Underweight: BMI below 18.5
• Normal weight: BMI 18.5-24.9
• Overweight: BMI 25-29.9
• Obese: BMI 30 or higher

For children and teens, BMI is age- and sex-specific.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters (e.g., 1.68 for 168 cm), and optionally age for more specific interpretation. All values must be valid (weight > 0, height > 0).

5. Frequently Asked Questions (FAQ)

Q1: Is BMI different for women than men?
A: The same BMI categories apply to both sexes, but women typically have higher body fat percentages than men at the same BMI.

Q2: How does age affect BMI interpretation?
A: Older adults may have slightly higher optimal BMI ranges compared to younger adults.

Q3: What's a healthy BMI for pregnancy?
A: Pre-pregnancy BMI determines recommended weight gain. Consult your healthcare provider for personalized advice.

Q4: Are there limitations to BMI?
A: BMI doesn't distinguish between muscle and fat, and may not be accurate for athletes, pregnant women, or the elderly.

Q5: Should children use this calculator?
A: Children's BMI is interpreted differently using age- and sex-specific percentiles rather than fixed categories.