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.
What If I Changed My Weight?
Explore how changes affect your results
How Your BMI Compares
Compared to the general population
Your BMI
24.2
Percentile
37th
You're in the ideal range!
Distribution
10th
19.5
25th
22.0
Median
26.5
75th
30.5
90th
35.0
Population Average
26.5
Ideal Range
18.5 - 24.9
Your Ranking
Top 37%
63% are higher
Tips Based on Your BMI
Personalized for Normal Weight
Maintain your healthy habits
You're in a healthy BMI range! Focus on maintaining the habits that got you here.
Challenge yourself with new fitness goals
Since you're at a healthy weight, you can focus on performance and fitness improvements.
Focus on nutrition quality
With weight maintenance handled, optimize for energy, recovery, and long-term health.
Related Health Calculators
Frequently Asked Questions
What is BMI and how is it calculated?
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.
What are the BMI 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.
Is BMI accurate for everyone?
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.
What health risks are associated with high BMI?
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.
How can I maintain a healthy BMI?
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.
What is a healthy BMI for my age?
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.
How often should I check my BMI?
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.
How this works
BMI = weight (kg) / height (m)². Interpretation bands follow WHO: <18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, 30+ obese. BMI is a screening heuristic for a population — not a diagnostic measure for an individual. It does not distinguish lean muscle mass from adipose tissue, which is why athletes can score "overweight" while being very healthy.
What this tool can’t do
- Does not distinguish muscle from fat. High-muscle individuals commonly score above the "normal" cutoff without being unhealthy.
- Does not account for fat distribution, which matters more for cardiovascular risk than total weight.
- Pediatric BMI requires age- and sex-specific percentile charts — use the child BMI calculator instead.
When to consult a professional
Talk to a licensed healthcare provider before using the output of this tool to make a medical decision, especially if you have an underlying condition, are pregnant, or are on medication that affects metabolism or fluid balance.
Sources
- [1]Centers for Disease Control and Prevention (CDC)Official sourcecdc.govAccessed Apr 21, 2026
- [2]National Institutes of Health (NIH)Official sourcenih.govAccessed Apr 21, 2026
- [3]World Health Organization (WHO)Official sourcewho.intAccessed Apr 21, 2026
Full-stack software engineer specializing in embedded systems, web architecture, and AI/ML. Founder of Practical Web Tools. Built the gesture-controlled drone IP acquired by KD Interactive (Aura Drone, sold on Amazon).