BMI Calculator

Step 1: Optionally select your gender and enter your age for context.

Step 2: Choose Metric or Imperial units using the tabs above the calculator.

Metric: Enter your weight in kilograms and height in centimetres (e.g. 70 kg, 175 cm).

Imperial: Enter your weight in pounds and height in feet and inches (e.g. 154 lbs, 5 ft 9 in).

Your BMI score, category, and visual scale will appear automatically as you type.

Note: BMI is a general informational tool only. Consult a healthcare professional for a full health assessment.

What is BMI?

Body Mass Index (BMI) is a simple numerical value calculated from a person's weight and height. It is used as a population-level screening indicator for weight categories that may be associated with health risks — not as a diagnostic tool.

How is BMI Calculated?

Metric Formula: BMI = weight (kg) ÷ height² (m). Example: 70 kg ÷ (1.75)² = 22.9

Imperial Formula: BMI = (weight (lbs) × 703) ÷ height² (inches). Example: (154 × 703) ÷ 69² = 22.7

Healthy BMI Ranges

BMI Limitations

BMI does not distinguish between muscle and fat, bone density differences, or fat distribution. Athletes with high muscle mass may be classified as overweight despite having low body fat. Similarly, older adults may have a "normal" BMI while having excess body fat due to muscle loss.

BMI vs Body Composition

While BMI uses only height and weight, body composition measurements (such as DEXA scans, skinfold tests, or bioelectrical impedance) measure actual body fat percentage. These provide a more accurate picture of health but require specialist equipment. BMI remains a widely used first-step screening tool due to its simplicity and accessibility.