BMI Calculator
Calculate Your BMI
BMI Categories
BMI is a screening tool and not a diagnostic tool. Consult a healthcare professional for medical advice.
Enter your weight and height to calculate BMI
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About BMI Calculator
Calculate your Body Mass Index (BMI) instantly. Supports metric and imperial units. Get your BMI category and healthy weight range. Free online tool.
How to Use
Step 1
Select your preferred unit system: Metric (kg, cm) or Imperial (lbs, inches)
Step 2
Enter your weight in kilograms or pounds
Step 3
Enter your height in centimeters or inches
Step 4
Click 'Calculate BMI' to see your result
Step 5
View your BMI number and category (Underweight, Normal, Overweight, Obese)
Step 6
Check your healthy weight range for your height
Step 7
Read personalized health recommendations based on your BMI
Step 8
Review the BMI categories reference table to understand ranges
Features & Benefits
- ✅Calculate BMI for adults (18+ years)
- ✅Support for metric units (kg, cm) and imperial units (lbs, inches)
- ✅Instant BMI calculation with one click
- ✅7 BMI categories: Severely Underweight, Underweight, Normal, Overweight, Obese I, II, III
- ✅Color-coded categories for easy understanding
- ✅Healthy weight range calculator for your height
- ✅Personalized health recommendations based on BMI
- ✅BMI categories reference table with ranges
- ✅Input validation to prevent unrealistic values
- ✅Clear button to reset calculator
- ✅Responsive design works on all devices
- ✅Medical disclaimer for responsible use
- ✅Educational information about BMI
- ✅100% browser-based - data never sent to server
- ✅100% free - no limits, no signup required
FAQs
What is BMI?
BMI (Body Mass Index) is a measure of body fat based on your height and weight. It's calculated by dividing weight (kg) by height squared (m²) in metric, or weight (lbs) × 703 / height squared (inches²) in imperial. BMI is used as a screening tool to identify potential weight problems in adults.
What is a healthy BMI?
A healthy BMI for adults is between 18.5 and 24.9 (Normal Weight). BMI below 18.5 is Underweight, 25-29.9 is Overweight, and 30+ is Obese. However, BMI is just one indicator of health and doesn't account for muscle mass, bone density, or body composition.
How accurate is BMI?
BMI is a useful screening tool but has limitations. It doesn't distinguish between muscle and fat, so athletes or muscular individuals may have high BMI despite low body fat. It also doesn't account for age, sex, ethnicity, or body composition. Use BMI as one of many health indicators, not the only one.
Can I use BMI for children?
This calculator is designed for adults (18+ years). Children and teens require BMI-for-age percentiles that account for age and sex, as their body composition changes during growth. Consult a pediatrician for children's BMI assessment.
What if I'm very muscular?
BMI doesn't distinguish between muscle and fat. Bodybuilders, athletes, and very muscular individuals may have high BMI (Overweight or Obese range) despite having low body fat. In these cases, body fat percentage, waist circumference, or other measurements are more accurate.
What's the difference between metric and imperial?
Metric uses kilograms (kg) for weight and centimeters (cm) for height. Imperial uses pounds (lbs) for weight and inches for height. The calculator automatically applies the correct formula for each system. Choose the system you're most comfortable with.
What should I do if my BMI is not in the normal range?
If your BMI is outside the normal range (18.5-24.9), consider consulting a healthcare professional. They can assess your overall health, body composition, and provide personalized advice on diet, exercise, and lifestyle changes. Don't make drastic changes without professional guidance.
Does BMI apply to everyone?
BMI has limitations for certain groups: pregnant women, athletes, bodybuilders, elderly adults, and people with certain medical conditions. It also doesn't account for ethnic differences in body composition. BMI is most accurate for average, sedentary adults.
How often should I check my BMI?
For general health monitoring, checking BMI monthly or quarterly is sufficient. If you're actively trying to lose or gain weight, weekly checks can help track progress. Remember that weight fluctuates daily due to water retention, so focus on trends over time, not daily changes.
What's the healthy weight range for my height?
The calculator shows your healthy weight range based on BMI 18.5-24.9 for your height. This range represents weights associated with the lowest health risks for average adults. However, your ideal weight depends on many factors including muscle mass, bone density, and overall health.
Is my data secure?
Yes! All BMI calculations happen entirely in your browser using JavaScript. Your weight, height, and results never leave your device and are not sent to any server, ensuring complete privacy and security.