BMI Calculator Online — Free, Instant Results
Check your Body Mass Index (BMI) to understand your health status.
Enter your height and weight to see your BMI.
About This Tool
Calculate your BMI with metric or imperial units
BMI (Body Mass Index) is a widely used health metric that helps assess whether you're at a healthy weight for your height. Our calculator supports both metric (kg/cm) and imperial (lbs/inches) units, with instant health category classification.
Privacy guaranteed. All calculations happen locally in your browser — no personal data is stored or transmitted.
Dual Units
Supports metric (kg/cm) and imperial (lbs/in).
Instant Results
Real-time BMI calculation as you type.
Health Categories
WHO-standard classification automatically shown.
100% Private
No data stored or transmitted.
Reference
BMI Categories (WHO Standard)
< 18.5
Underweight
18.5 – 24.9
Normal Weight
25 – 29.9
Overweight
≥ 30
Obesity
Use Cases
When to Use BMI Calculator
BMI is a quick screening tool used by individuals, healthcare providers, and fitness professionals to assess weight relative to height.
Health Screening
Get a quick overview of whether your weight falls within a healthy range for your height.
Fitness Goal Setting
Use your current BMI as a baseline to set realistic weight loss or muscle gain targets.
Pre-Appointment Check
Calculate BMI before a doctor or nutritionist appointment to arrive informed.
Progress Tracking
Track BMI changes over weeks or months to measure the impact of diet and exercise changes.
Family Health Monitoring
Check BMI for family members of different ages and heights to monitor overall household health.
Insurance & Medical Forms
Calculate BMI to fill in health questionnaires, insurance forms, or medical intake documents.
FAQ
Frequently Asked Questions
Is BMI an accurate measure of health?
BMI is a useful screening tool but has limitations. It doesn't distinguish between muscle and fat mass, so athletes may have high BMI despite being healthy. Best used alongside other health indicators.
What BMI is considered healthy?
A BMI between 18.5 and 24.9 is generally considered healthy for adults. Ideal BMI can vary based on age, sex, muscle mass, and ethnicity. Consult a healthcare provider for personalized advice.
Does age affect BMI?
Yes, BMI interpretation can vary with age. Older adults may have a slightly higher healthy BMI range. Children and teens use age and sex-specific BMI percentiles rather than adult categories.
Can I use BMI if I'm very muscular?
BMI may not be accurate for very muscular individuals, as muscle weighs more than fat. Athletes and bodybuilders may have high BMI despite low body fat. Consider body composition analysis.