⚖️ BMI Calculator
Calculate your Body Mass Index and check your health status
What is BMI (Body Mass Index)?
Body Mass Index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. It's a screening tool used to identify whether a person is underweight, at a healthy weight, overweight, or obese.
BMI is calculated by dividing a person's weight by the square of their height. While BMI doesn't directly measure body fat, research shows it correlates with direct measures of body fat and can be used to screen for weight categories that may lead to health problems.
How to Calculate BMI
- Choose Unit System: Select Metric (kg, cm) or Imperial (lbs, ft/in)
- Enter Weight: Input your current weight in kilograms or pounds
- Enter Height: Input your height in centimeters or feet and inches
- View Results: Your BMI is calculated automatically with category and health advice
- Check Chart: Compare your BMI against the standard BMI ranges
BMI Calculation Examples
Example 1: Normal Weight (Metric)
Person weighing 70 kg with height 170 cm.
- Weight: 70 kg
- Height: 170 cm (1.7 m)
- BMI: 70 ÷ (1.7)² = 24.2
- Category: Normal Weight
Example 2: Overweight (Imperial)
Person weighing 200 lbs with height 5 feet 8 inches.
- Weight: 200 lbs
- Height: 68 inches
- BMI: (200 ÷ 68²) × 703 = 30.4
- Category: Obese
Example 3: Underweight
Person weighing 50 kg with height 175 cm.
- Weight: 50 kg
- Height: 175 cm (1.75 m)
- BMI: 50 ÷ (1.75)² = 16.3
- Category: Underweight
BMI Formula
Metric Formula: BMI = weight (kg) ÷ [height (m)]²
Imperial Formula: BMI = [weight (lbs) ÷ height (in)²] × 703
BMI Categories (WHO Standards)
- Underweight: BMI less than 18.5
- Normal Weight: BMI 18.5 to 24.9
- Overweight: BMI 25 to 29.9
- Obese Class I: BMI 30 to 34.9
- Obese Class II: BMI 35 to 39.9
- Obese Class III: BMI 40 or greater
Frequently Asked Questions
What is a healthy BMI?
A BMI between 18.5 and 24.9 is considered healthy for most adults. However, BMI is just one indicator of health and should be considered alongside other factors.
Is BMI accurate?
BMI is a useful screening tool but has limitations. It doesn't distinguish between muscle and fat, and may not be accurate for athletes, bodybuilders, pregnant women, or elderly individuals. Consult a healthcare provider for a complete health assessment.
How often should I check my BMI?
It's recommended to check your BMI every few months if you're actively managing your weight, or annually as part of routine health monitoring.
Can BMI be used for children?
BMI can be used for children, but it's interpreted differently using age and sex-specific percentile charts. This calculator is designed for adults aged 18 and over.
What if my BMI is too high or too low?
If your BMI is outside the normal range, consult with a healthcare provider. They can assess your overall health and provide personalized recommendations for diet, exercise, and lifestyle changes.
Does BMI account for muscle mass?
No, BMI doesn't distinguish between muscle and fat. Athletes and bodybuilders may have high BMI due to muscle mass but low body fat. In such cases, other measurements like body fat percentage are more accurate.