Body Composition · No. 01Easy · 1-2 min

BMI Calculator
read in plain numbers.

Body Mass Index from height and weight, in metric or imperial. A useful first screen — but read the result alongside body fat percentage and waist-to-height before drawing conclusions.

Free BMI Calculator

Calculate your Body Mass Index instantly with metric or imperial units. Get your BMI category and health risk assessment.

Calculator

Enter your measurements to calculate your Body Mass Index (BMI)

Unit System
Metric
Imperial
Male

What is Body Mass Index (BMI)?

Body Mass Index (BMI) is a widely used screening tool that measures body weight relative to height. It provides a simple numeric measure to classify individuals as underweight, normal weight, overweight, or obese based on established health guidelines. While BMI is a useful population-level indicator, it has limitations for individuals since it doesn't distinguish between muscle mass and fat mass. Athletes and very muscular individuals may have higher BMIs despite having healthy body compositions.

How to Calculate BMI

BMI = Weight (kg) ÷ Height² (m²) Note: Imperial inputs (pounds/feet/inches) are automatically converted to metric units for calculation.

Formula

BMI = Weight (kg) ÷ Height² (m²)

BMI Categories (Adults)

BMI RangeCategory
Below 18.5Underweight
18.5 - 24.9Normal Weight
25.0 - 29.9Overweight
30.0 - 34.9Obesity Class I
35.0 - 39.9Obesity Class II
40.0 and aboveObesity Class III

Tips & Limitations

Does not distinguish between muscle and fat mass
May not be accurate for athletes, elderly, or children
Does not account for bone density or body frame size
May vary by ethnicity and population groups

Medical Disclaimer

This BMI calculator is for informational and educational purposes only. Results should not replace professional medical advice, diagnosis, or treatment. BMI is a screening tool and may not reflect individual health status accurately. Always consult with qualified healthcare professionals for personalized health assessments, especially if your BMI indicates health risks or if you have concerns about your weight or overall health.

Frequently Asked Questions

Save your BMI.
Begin the record.

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