Health & Fitness

BMI Calculator

Calculate your Body Mass Index using your height and weight. Understand your BMI category and healthy weight range.

Calculate Your BMI

Height (cm)

Weight (kg)

What Is BMI?

BMI (Body Mass Index) is a measure that uses your height and weight to estimate if you are at a healthy weight. It is widely used as a general screening tool, though it has limitations and does not directly measure body fat.

How Is BMI Calculated?

BMI is calculated using this formula:

BMI = weight (kg) / height (m)²

For imperial units: BMI = (weight (lbs) / height (inches)²) × 703

What Do BMI Results Mean?

BMI values are categorized as follows: underweight (below 18.5), normal weight (18.5-25), overweight (25-30), and obese (above 30). These categories are general guidelines for adults and may not apply to athletes, children, pregnant women, or elderly individuals.

BMI Limitations

BMI is a screening tool and not a diagnostic measure. It does not account for muscle mass, bone density, overall body composition, or individual variations. Athletes with high muscle mass may have a high BMI despite being healthy. BMI should be one of several factors considered when evaluating health.

Health Disclaimer

This calculator provides estimates for informational purposes only. It is not medical advice or a diagnosis. Individual health and nutritional needs can vary. Consult with a healthcare professional for personalized guidance.

Calculated Locally

All calculations are performed in your browser. Your health information is never stored or transmitted.

Frequently Asked Questions

Common questions and answers about this tool

Body Mass Index (BMI) is calculated as weight in kilograms divided by height in meters squared (kg/m²). It's a screening tool to categorize weight status. For imperial units, multiply (weight in pounds / height in inches²) by 703. Use our unit converter to convert between metric and imperial measurements.

A healthy BMI is typically 18.5-24.9. Under 18.5 is underweight, 25-29.9 is overweight, and 30+ is obese. However, BMI doesn't account for muscle mass, bone density, or body composition. Track your progress with our percentage calculator to monitor BMI changes over time.

BMI is a general screening tool but doesn't distinguish between muscle and fat. Athletes with high muscle mass, pregnant women, elderly individuals, and growing children may need alternative assessments like body fat percentage or waist-to-hip ratio. Consider using our BMR calculator to estimate your daily calorie needs based on your body composition.

Yes, our calculator supports both metric (cm, kg) and imperial (inches, lbs) units. Simply select your preferred unit system using the toggle button, and the calculator will automatically adjust the formula.

BMI categories are: Underweight (< 18.5), Normal weight (18.5-24.9), Overweight (25-29.9), Obesity Class I (30-34.9), Obesity Class II (35-39.9), and Obesity Class III (≥ 40). These ranges are for adults aged 20 and above.

A high BMI may indicate increased health risks, but it's just one indicator. Consult with a healthcare provider who can assess your overall health, body composition, family history, and other factors to provide personalized guidance.

Related Tools

Health & Fitness

BMR Calculator

Calculate your Basal Metabolic Rate using the Mifflin-St Jeor equation. Estimate your daily calorie needs based on activity level.

Converters

Unit Converter

Convert between length, weight, area, volume, temperature, speed, time, digital storage, energy, and pressure units instantly.

Productivity Tools

Percentage Calculator

Calculate percentages, percentage increase, decrease, difference, and reverse percentages instantly with step-by-step formulas.