BMI Calculator - Body Mass Index Calculator
Calculate your Body Mass Index (BMI) instantly. Free, accurate, and works with metric or imperial units. Know if you're underweight, normal, overweight, or obese.
< 18.5
18.5 - 24.9
25 - 29.9
≥ 30
BMI Distribution Chart
Your BMI indicates a normal weight. Maintain a balanced diet and regular exercise to stay healthy.
How to Use BMI Calculator
Calculate your Body Mass Index in 3 simple steps:
Select Your Details
Choose your gender and enter your age. These help provide more accurate health recommendations based on your demographics.
Enter Measurements
Input your height and weight. You can use the slider for quick adjustments or type exact values. Switch between metric (kg/cm) and imperial (lb/ft) units.
View Your Results
See your BMI instantly with color-coded category (underweight, normal, overweight, obese). Get your healthy weight range and personalized advice.
BMI Calculation Formula
Example Calculation
Weight: 70 kg
Height: 170 cm = 1.70 meters
Formula: 70 ÷ (1.70 × 1.70)
BMI: 70 ÷ 2.89 = 24.2
Category: Normal Weight (18.5 - 24.9)
Health Status: Healthy weight range - maintain with balanced diet and exercise!
BMI Categories & Health Risks
Underweight (BMI < 18.5)
Health Risks: Malnutrition, weakened immune system, osteoporosis, anemia
Recommendation: Increase calorie intake with nutrient-rich foods. Consult a dietitian for a healthy weight gain plan.
Normal Weight (BMI 18.5 - 24.9)
Health Status: Healthy weight range with lower disease risk
Recommendation: Maintain current weight with balanced diet, regular exercise, and healthy lifestyle habits.
Overweight (BMI 25 - 29.9)
Health Risks: Increased risk of heart disease, type 2 diabetes, high blood pressure
Recommendation: Focus on portion control, increase physical activity, and consider professional guidance for weight management.
Obese (BMI ≥ 30)
Health Risks: High risk of cardiovascular disease, diabetes, certain cancers, sleep apnea
Recommendation: Consult healthcare provider immediately. Create comprehensive weight loss plan with medical supervision.
Why Use Our BMI Calculator?
Instant Results
Get your BMI calculated instantly as you adjust values. Real-time updates with visual color-coded categories.
Metric & Imperial
Switch between kg/cm and lb/ft units. Works for users worldwide with automatic conversions.
100% Accurate
Uses WHO-approved BMI formula. Get accurate results matching medical standards globally.
Visual Charts
See where you stand with interactive BMI range charts and healthy weight recommendations.
Private & Secure
All calculations happen in your browser. Your health data never leaves your device.
Mobile Ready
Calculate BMI on your phone, tablet, or computer with the same great experience.
Frequently Asked Questions
What is BMI and why is it important?
BMI (Body Mass Index) is a measure of body fat based on height and weight. It's important because it helps assess if you're at a healthy weight, which reduces risk of diseases like diabetes, heart disease, and certain cancers.
Is BMI accurate for everyone?
BMI is a useful screening tool but not perfect. It doesn't account for muscle mass, bone density, or body composition. Athletes with high muscle mass may have high BMI but low body fat. Consult a healthcare provider for complete health assessment.
What is a healthy BMI range?
A healthy BMI is between 18.5 and 24.9 for adults. Below 18.5 is underweight, 25-29.9 is overweight, and 30+ is obese. These ranges may vary slightly by ethnicity and individual factors.
How often should I check my BMI?
Check your BMI every 3-6 months if you're actively trying to lose or gain weight. For general health monitoring, checking 2-4 times a year is sufficient. Focus more on overall health trends than day-to-day fluctuations.
Can I use this BMI calculator for children?
This calculator works for ages 2+, but BMI interpretation for children and teens is different. Children's BMI must be compared to growth charts specific to age and gender. Consult a pediatrician for accurate child BMI assessment.
What should I do if my BMI is high?
If your BMI is 25 or higher, focus on healthy eating, regular exercise, and lifestyle changes. Consult a healthcare provider or registered dietitian for personalized weight management plan. Small, consistent changes lead to sustainable results.
Does BMI differ for men and women?
The BMI formula is the same for both genders, but women naturally have more body fat than men. Our calculator considers gender for more accurate health recommendations. However, the standard BMI categories (18.5-24.9) apply to both.
Can I switch between kg and lbs?
Yes! Use the unit selector at the top to switch between metric (kg/cm) and imperial (lb/ft) units. The calculator automatically converts your inputs and updates results instantly.