BMI Calculator - Calculate Body Mass Index Online Free

How to Use the BMI Calculator

1. Enter your weight — in pounds or kilograms
2. Enter your height — in feet/inches or centimeters
3. Get instant BMI — see your score, category, and a color-coded indicator
4. View healthy range — the tool shows the ideal weight range for your height
5. Switch units — toggle between imperial and metric at any time

Understand your BMI category: Underweight (<18.5), Normal (18.5-24.9), Overweight (25-29.9), or Obese (30+). All calculations happen in your browser — nothing is saved or uploaded.

Features

• Instant calculation — updates as you type
• Dual units — imperial (lbs/ft) and metric (kg/cm)
• BMI categories — color-coded results
• Healthy weight range — shows ideal weight for your height
• Visual indicator — gauge-style display

Use Cases

• Health check-in — quickly assess where your BMI falls as part of a routine health screening
• Fitness tracking — track BMI changes over weeks or months as you lose or gain weight
• Doctor visits — get a preliminary BMI reading before discussing weight management with your healthcare provider
• Insurance applications — some health insurance questionnaires ask for BMI; get an instant estimate
• Weight loss progress — monitor how your BMI category changes as you reach milestones

FAQ

What is a healthy BMI?

A BMI between 18.5 and 24.9 is considered healthy (normal weight range). Below 18.5 is underweight, 25-29.9 is overweight, and 30+ is obese.

Can BMI be inaccurate for athletes?

Yes. BMI doesn’t distinguish between muscle and fat. Athletes and bodybuilders with high muscle mass may have a high BMI despite being very healthy. Use the body fat calculator for a more accurate picture.

Is BMI different for men and women?

The same BMI ranges apply to both men and women. However, women typically have higher body fat percentages than men at the same BMI.

How often should I check my BMI?

Once a month is sufficient for tracking general trends. BMI changes slowly, so daily checks won’t show meaningful differences.

Tips

• Take BMI measurements at the same time of day (morning is best) for consistent tracking
• BMI is a screening tool, not a diagnostic — use it alongside other health metrics
• For children and teens, use age-and-sex-specific BMI percentile charts rather than adult categories