BMI Calculator
Calculate your Body Mass Index (BMI) instantly with our free calculator. Supports both metric (kg, cm) and imperial (lbs, ft/in) units. Get your BMI category, see where you fall on the BMI scale with a visual gauge, and discover your healthy weight range based on WHO guidelines.
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How to Use
- 1 Choose your unit system — Select between Metric (kg, cm) or Imperial (lbs, feet/inches) using the toggle buttons at the top.
- 2 Enter your height — For metric, enter height in centimeters (e.g., 170). For imperial, enter feet and inches separately (e.g., 5 feet 7 inches).
- 3 Enter your weight — For metric, enter weight in kilograms (e.g., 70). For imperial, enter weight in pounds (e.g., 154).
- 4 View your results — Your BMI is calculated instantly with a color-coded category (Underweight, Normal, Overweight, Obese) and visual gauge showing where you fall on the BMI scale.
- 5 Check healthy weight range — See the recommended healthy weight range for your height based on BMI guidelines (18.5-24.9). Copy your results with one click.
Frequently Asked Questions
What is BMI and how is it calculated?
BMI (Body Mass Index) is a screening tool that estimates body fat based on your height and weight. It's calculated using the formula: weight(kg) / height(m)² for metric units, or weight(lbs) × 703 / height(inches)² for imperial units. Healthcare professionals use BMI as an initial assessment tool to categorize weight status and identify potential health risks.
What do the BMI categories mean?
The four BMI categories are: Underweight (BMI < 18.5) may indicate nutritional deficiency; Normal weight (BMI 18.5-24.9) is considered a healthy weight for your height; Overweight (BMI 25-29.9) may increase health risks; and Obese (BMI ≥ 30) significantly increases health risks. These are general guidelines established by the World Health Organization (WHO).
What are the limitations of BMI?
BMI doesn't account for muscle mass, bone density, overall body composition, or distribution of fat. It may not be accurate for athletes, bodybuilders, pregnant women, elderly individuals, or certain ethnic groups. BMI is a screening tool, not a diagnostic tool for body fatness or health. For a comprehensive health assessment, consult with your healthcare provider who can consider additional factors like waist circumference, lifestyle, and family history.
Is my data private and secure?
All calculations happen directly in your browser (client-side). No data is sent to any servers or stored anywhere. Your height, weight, and BMI results are completely private. There's no tracking, no accounts required, and no data collection whatsoever. This privacy-first approach applies to all Toolisti tools.