BMI Calculator – Body Mass Index
Free BMI calculator (Body Mass Index) with metric and imperial units. Fast BMI classification and health tips with examples on how to calculate BMI.
Start Calculating
How to calculate BMI
- Metric: BMI = weight(kg) ÷ height²(m).
- Imperial: BMI = 703 × weight(lb) ÷ height²(in).
- Categories: <18.5 underweight; 18.5–24.9 normal; 25–29.9 overweight; ≥30 obese.
Examples
- 1.75 m and 68 kg → BMI ≈ 22.2 (normal).
- 5'9" and 170 lb → BMI ≈ 25.1 (borderline overweight).
Enter Body Measurements
Input Examples
BMI Result
Important Notice
BMI is for reference only and not suitable for pregnant women, children, athletes and other special populations. Consult a professional doctor if you have health concerns.
Features
Multiple Units
Supports metric (cm/kg) and imperial (ft/in/lbs) units
Health Assessment
Provides health assessment and recommendations based on BMI
Instant Calculation
Calculates BMI immediately after entering height and weight
Secure Usage
All calculations are performed locally, no data uploaded
Helpful Tips
BMI is only a reference value and cannot fully represent health status
Athletes and muscular individuals may have higher BMI but are not necessarily unhealthy
A healthy lifestyle is more important than an ideal BMI
Regular monitoring of BMI changes is more meaningful than a single measurement
Consult a professional doctor if you have health concerns
How to Use
Choose Units
Select metric (cm/kg) or imperial (ft/in/lbs)
Enter Height & Weight
Enter your height and weight in the corresponding fields
View Results
The system automatically calculates BMI and provides health advice
Frequently Asked Questions
What is BMI?
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What is BMI?
BMI (Body Mass Index) is an important standard for measuring body fat and health. It is calculated based on height and weight using the formula: BMI = Weight(kg) ÷ Height²(m).
What are the BMI categories?
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What are the BMI categories?
BMI < 18.5 is underweight; 18.5-24.9 is normal weight; 25.0-29.9 is overweight; ≥30.0 is obese.
What are the limitations of BMI?
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What are the limitations of BMI?
BMI does not distinguish between muscle and fat, muscular individuals may have higher BMI; not suitable for children and adolescents under 18; not suitable for pregnant and breastfeeding women; age, gender, bone density and other factors are not considered.
How to use the BMI calculator?
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How to use the BMI calculator?
Select your preferred units (metric or imperial), enter your height and weight, then click the "Calculate BMI" button. The system will immediately display your BMI value, weight classification, and health recommendations.