BMI Calculator
Calculate your Body Mass Index (BMI) and find out if you're in a healthy weight range. Get personalized insights based on your height and weight.
Your BMI Results
Your BMI
24.2
Category
Normal Weight
Enter Your Measurements
5'6"
BMI Categories
Your BMI Results
Your BMI
24.2
Category
Normal Weight
Quick Answer: How to Calculate Your BMI
To calculate your BMI (Body Mass Index), divide your weight in kilograms by your height in meters squared. The formula is BMI = weight (kg) / height (m)². For imperial units, use BMI = (weight in pounds x 703) / (height in inches)². A BMI of 18.5-24.9 is considered normal weight, under 18.5 is underweight, 25-29.9 is overweight, and 30+ is obese.
Key Facts About BMI
- BMI formula: weight (kg) divided by height (m) squared, or (weight in lbs x 703) / (height in inches)²
- Normal BMI range is 18.5 to 24.9 for adults
- BMI under 18.5 is classified as underweight
- BMI of 25-29.9 is classified as overweight
- BMI of 30 or higher indicates obesity
- BMI does not directly measure body fat or distinguish between muscle and fat mass
- BMI accuracy varies for athletes, elderly, and pregnant women
- World Health Organization (WHO) established the standard BMI categories
What is BMI? (Body Mass Index Definition)
Body Mass Index (BMI) is a numerical value calculated from your height and weight that serves as a screening tool to categorize individuals into weight categories. Developed by Belgian mathematician Adolphe Quetelet in the 1830s, BMI is widely used by healthcare professionals to assess whether a person is underweight, normal weight, overweight, or obese.
BMI Formula
Metric: BMI = weight (kg) / height (m)²
Imperial: BMI = (weight (lbs) × 703) / height (in)²
How It Works
- Measure your weight in kilograms or pounds
- Measure your height in meters or inches
- Square your height (multiply it by itself)
- Divide your weight by your height squared
- Compare your result to the BMI categories
Limitations
BMI doesn't distinguish between muscle and fat mass. Athletes and bodybuilders may have high BMIs due to muscle mass rather than excess fat. Age, sex, ethnicity, and body composition are not accounted for. Always consult healthcare providers for comprehensive health assessments.
Related Health Calculators
Frequently Asked Questions
Body Mass Index (BMI) is a measure of body fat based on height and weight. It's calculated by dividing weight in kilograms by height in meters squared (kg/m²). For imperial units, the formula is: BMI = (weight in pounds × 703) / (height in inches)². While BMI doesn't directly measure body fat, it's a useful screening tool for weight categories.
BMI categories are: Underweight (below 18.5), Normal weight (18.5-24.9), Overweight (25-29.9), Obese Class I (30-34.9), Obese Class II (35-39.9), and Obese Class III (40 or higher). These categories help identify potential health risks associated with weight.
BMI has limitations. It doesn't distinguish between muscle and fat, so muscular athletes may have high BMIs despite being healthy. It also doesn't account for age, sex, ethnicity, or body composition. For example, older adults may have more body fat at the same BMI as younger adults. BMI should be used alongside other health assessments.
Higher BMI is associated with increased risk of heart disease, high blood pressure, type 2 diabetes, gallstones, sleep apnea, certain cancers, and osteoarthritis. However, BMI is just one factor - lifestyle, genetics, and other health markers also play important roles in overall health.
To maintain a healthy BMI: eat a balanced diet rich in fruits, vegetables, whole grains, and lean proteins; exercise regularly (at least 150 minutes of moderate activity per week); limit processed foods and sugary drinks; get adequate sleep; manage stress; and have regular health check-ups.
For adults 20 and older, a healthy BMI is typically 18.5-24.9 regardless of age. However, research suggests older adults (65+) may benefit from a slightly higher BMI (23-30) as some extra weight can be protective. For children and teens, BMI is interpreted using age-specific percentile charts.
Check your BMI once every few months or when you notice significant changes in your weight. Regular monitoring helps track progress if you are working toward a weight goal. However, focus on overall health indicators rather than BMI alone - consider energy levels, fitness, and how your clothes fit.
Your BMI Results
Your BMI
24.2
Category
Normal Weight
Medical Disclaimer
This calculator is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult with a qualified healthcare provider before making any health-related decisions.