BMI Calculator for Teens (Ages 13-19 Years)
Calculate Body Mass Index (BMI) percentile for teenagers ages 13-19 using CDC growth charts. This teen BMI calculator provides accurate BMI-for-age percentiles that account for the physical changes happening during adolescence. Understanding your BMI can help you make informed decisions about health, but remember—BMI is just one measure of health, not a measure of your worth or value as a person.
💜 Important Message for Teens: Your body is changing and developing—that's completely normal. BMI doesn't define you or determine your value. If you're experiencing negative thoughts about your body, struggling with food, or feeling anxious about weight, please talk to a trusted adult, counselor, or healthcare provider. Body dissatisfaction at age 16 can predict eating disorders and depression in your twenties, so addressing concerns early with professional support is crucial for your wellbeing.
Teen BMI Calculator
Your BMI Results
Understanding BMI During Adolescence
The teenage years bring dramatic physical, hormonal, and emotional changes. Your body is developing rapidly—girls typically experience major growth spurts around ages 11-14, while boys often see theirs around 13-16. During puberty, body composition changes significantly: girls naturally gain more body fat (necessary for reproductive health), while boys develop more muscle mass.
BMI during adolescence must account for these age- and sex-specific changes, which is why we use BMI-for-age percentiles rather than adult BMI categories. These percentiles compare your BMI to other teens of the same age and biological sex from CDC growth charts representing diverse populations across the United States.
Why BMI Percentiles for Teens?
A BMI of 22 might be healthy for an 18-year-old but could indicate overweight for a 13-year-old. Percentiles provide age-appropriate context. According to 2023-2024 data, 16.1% of youth ages 6-17 have obesity, and rates have more than tripled since the mid-1970s. Black and Latino youth experience substantially higher obesity rates compared to Asian and White peers, reflecting systemic inequities in food access, built environments, and healthcare.
BMI Calculation Formulas
Basic BMI Formula
The fundamental BMI calculation:
Or using imperial units:
Where:
- Weight = Body weight in kilograms or pounds
- Height = Height in meters or inches
- 703 = Conversion factor for imperial units
BMI Percentile Calculation (LMS Method)
CDC uses the LMS method to determine percentiles:
Where:
- \( L \) = Box-Cox transformation power (accounts for distribution skewness)
- \( M \) = Median BMI value for specific age and sex
- \( S \) = Generalized coefficient of variation
- \( Z \) = Z-score (standard deviations from median)
- Percentile = Standard normal cumulative distribution of Z
L, M, and S values are age- and sex-specific from CDC growth charts
Example Calculation
Example: 16-year-old girl, 5 feet 7 inches (67 inches), 130 pounds
This BMI of 20.4 corresponds to approximately the 50th percentile for 16-year-old girls = healthy weight range.
BMI Categories for Teenagers
| BMI Percentile Range | Weight Category | What It Means |
|---|---|---|
| Less than 5th percentile | Underweight | BMI lower than 95% of teens your age and sex; may indicate inadequate nutrition or health concerns |
| 5th to 84th percentile | Healthy Weight | BMI in the normal range for your age and sex; appropriate weight for height |
| 85th to 94th percentile | Overweight | BMI higher than 85-94% of teens your age and sex; may increase health risks |
| 95th percentile or above | Obesity | BMI at or above 95% of teens your age and sex; significantly elevated health risks |
Understanding Your Percentile: If your BMI is at the 60th percentile, it means your BMI is the same as or higher than 60% of teens your age and sex, and lower than 40%. The healthy range is broad (5th-84th percentile) because bodies naturally vary. What matters most is your overall health, growth pattern, habits, and how you feel—not just a number.
Body Image and Mental Health in Teens
Research published in The Lancet Psychiatry (2024) followed over 2,000 teens and found that body dissatisfaction at age 16 strongly predicted eating disorders and depression symptoms well into the twenties—even after accounting for genetics and family background. This connection was particularly strong for girls, reflecting greater societal pressure on young women to meet unrealistic appearance standards.
The Body Image Crisis
In our current culture saturated with filtered social media images, comparison culture, and appearance-focused messaging, many teens struggle with body image:
- Girls experience stronger long-term effects: Cultural pressures around thinness translate into greater mental health impacts
- Boys face increasing pressure: Muscular ideal and "fitspiration" content create body dissatisfaction in boys too
- Social media amplification: Constant exposure to edited, curated bodies distorts perception of "normal"
- Diet culture messaging: Weight-focused language and diet talk normalize unhealthy relationships with food and bodies
- Weight stigma and bullying: Weight-based teasing significantly harms mental health and often worsens weight issues
Warning Signs of Body Image Issues:
- Constantly thinking about body size, shape, or weight
- Frequent negative comments about your appearance
- Avoiding activities, social situations, or photos due to body concerns
- Comparing your body to others frequently
- Feeling anxious or distressed when eating around others
- Excessive exercise that feels compulsive rather than enjoyable
- Restricting foods, skipping meals, or following rigid food rules
- Preoccupation with "clean eating" or fear of certain foods
If you recognize these signs, please reach out for help. Talk to a parent, school counselor, trusted adult, or call the National Eating Disorders Association Helpline: 1-800-931-2237 (text "NEDA" to 741741).
Eating Disorders in Adolescence
Eating disorders are serious mental illnesses with the second-highest mortality rate of any psychiatric disorder. They affect people of all genders, sizes, races, and backgrounds:
- Anorexia Nervosa: Severe food restriction, intense fear of weight gain, distorted body image
- Bulimia Nervosa: Episodes of binge eating followed by purging (vomiting, laxatives, excessive exercise)
- Binge Eating Disorder: Recurrent episodes of eating large amounts with loss of control
- ARFID: Avoidance/restriction of food unrelated to weight concerns (sensory issues, fear of adverse consequences)
- Atypical Anorexia: All criteria for anorexia except person is not underweight—can be just as dangerous
⚠️ Eating Disorder Emergency Signs - Get Help Immediately:
- Dramatic weight loss or weight fluctuations
- Fainting, dizziness, or difficulty concentrating
- Irregular or absent menstrual periods
- Feeling cold all the time (even in warm weather)
- Hair loss or growth of fine body hair (lanugo)
- Suicide thoughts or self-harm behaviors
- Severe restriction or refusing to eat meals
- Evidence of purging (bathroom use after meals, dental erosion)
Contact: National Eating Disorders Association Helpline 1-800-931-2237 | Crisis Text Line: Text "NEDA" to 741741 | National Suicide Prevention Lifeline: 988
Health Implications for Teens
Physical Health Risks by Weight Category
Underweight (BMI < 5th percentile):
- Delayed puberty and stunted growth
- Weakened immune system and frequent illness
- Nutrient deficiencies (iron, calcium, vitamins)
- Low energy and chronic fatigue
- Bone density issues increasing fracture risk
- Irregular or absent menstrual periods in girls
- May indicate eating disorder, malabsorption, or medical condition
Overweight/Obesity (BMI ≥ 85th percentile):
- Type 2 diabetes (increasingly common in teens)
- High blood pressure and high cholesterol
- Nonalcoholic fatty liver disease (NAFLD)
- Sleep apnea disrupting sleep quality and growth hormone release
- Joint problems and orthopedic complications
- Polycystic ovary syndrome (PCOS) in girls
- Increased risk for adult obesity and chronic diseases
- Psychosocial challenges including depression, anxiety, social isolation
Mental and Emotional Health
Weight status significantly impacts teen mental health, though the relationship is complex and bidirectional:
- Depression and Anxiety: Higher rates in teens with obesity or eating disorders
- Low Self-Esteem: Negative body image affects confidence across life domains
- Social Withdrawal: Avoiding activities due to body shame limits social development
- Academic Impact: Mental health struggles and health issues affect school performance
- Substance Use: Unhealthy coping mechanisms for body image distress
- Weight Stigma: Discrimination and bullying cause significant psychological harm—often worse than weight itself
Healthy Lifestyle Strategies for Teens
Nutrition Without Diet Culture
Reject diet culture and focus on nourishing your growing body:
- Eat Regular Meals: Don't skip meals, especially breakfast; your brain needs fuel for school
- Honor Hunger: Listen to your body's hunger cues; restriction backfires long-term
- Balanced Variety: Include fruits, vegetables, whole grains, proteins, dairy, and yes—treats and fun foods too
- Ditch "Good/Bad" Food Labels: All foods fit; rigid rules increase eating disorder risk
- Limit Sugary Drinks: Water is best for hydration; limit soda and energy drinks
- Family Meals: Eating together improves nutrition, communication, and mental health
- Intuitive Eating: Trust your body; eat when hungry, stop when satisfied
- Avoid Dieting: Dieting in teens predicts weight gain and eating disorders—not weight loss
✓ The Truth About Teen Dieting: Research consistently shows that teenagers who diet are at higher risk for weight gain (not loss) over time, and 2-3 times more likely to develop eating disorders. Your body is still growing and developing—it needs adequate nutrition. Focus on healthy behaviors (balanced eating, joyful movement, adequate sleep) rather than weight loss.
Physical Activity and Movement
- Find What You Enjoy: Sports, dance, hiking, swimming, skateboarding—movement should be fun, not punishment
- 60 Minutes Daily: Aim for at least 1 hour of moderate-to-vigorous activity most days
- Strength and Bone-Building: Include activities like running, jumping, resistance training 3x weekly
- Make it Social: Exercise with friends, join teams or clubs
- Limit Screens: Maximum 2 hours recreational screen time daily; take movement breaks
- Active Transportation: Walk or bike to school/friends when possible
- Listen to Your Body: Rest when tired; exercise shouldn't feel compulsive or punishing
Sleep—The Forgotten Health Factor
Teens need 8-10 hours of sleep nightly, but most get far less. Poor sleep disrupts hunger hormones, increases cravings, and affects mood, academic performance, and physical health:
- Consistent Schedule: Same bedtime and wake time, even weekends
- Screen Curfew: No phones/screens 1 hour before bed (blue light disrupts melatonin)
- Cool, Dark Bedroom: Optimal sleep environment
- Relaxation Routine: Reading, music, meditation to wind down
- Limit Caffeine: No caffeine after 2pm; avoid energy drinks
Mental Health Support
- Talk About Feelings: Open communication with trusted adults
- Challenge Negative Thoughts: Body-positive affirmations; focus on what your body can do
- Curate Social Media: Unfollow accounts that trigger comparison; follow body-positive, diverse content
- Seek Professional Help: Therapist, school counselor if struggling with body image, eating, or mood
- Build Self-Worth Beyond Appearance: Invest in hobbies, skills, relationships, values
- Support Friends: Avoid body talk, diet discussions; create judgment-free spaces
When to Seek Medical Advice
Consult a healthcare provider if you experience:
- BMI above 85th percentile: Screening for blood pressure, cholesterol, glucose
- BMI below 5th percentile: Evaluation for growth issues, nutrient deficiencies, underlying conditions
- Rapid Weight Changes: Significant gain or loss over short period
- Growth Concerns: Not growing as expected for age
- Irregular Periods: Absent, very irregular, or painful menstruation
- Eating Disorder Signs: Restrictive eating, purging behaviors, preoccupation with weight/food
- Mental Health Struggles: Depression, anxiety, body image distress, self-harm thoughts
- Physical Symptoms: Chronic fatigue, dizziness, joint pain, sleep problems
Healthcare Advocacy: You deserve respectful, weight-neutral healthcare focused on health behaviors and wellbeing—not just weight. If a healthcare provider makes you feel judged or focuses only on weight without addressing your concerns, it's okay to advocate for yourself or seek a different provider. Consider asking: "Can we discuss health habits and my concerns without focusing only on weight?"
Official Government & Medical Resources
Access trusted information from official health agencies and medical organizations:
Federal Health Agencies
CDC Teen BMI Calculator CDC Growth Charts NIH Physical Activity for Teens MyHealthfinder - Teen NutritionMental Health & Eating Disorder Support
NEDA Helpline: 1-800-931-2237 988 Suicide & Crisis Lifeline NIMH Eating Disorders Information MentalHealth.gov Teen ResourcesMedical Organizations
American Academy of Pediatrics HealthyChildren.org - Teen HealthFrequently Asked Questions
A healthy BMI percentile for teens is between the 5th and 84th percentile. This wide range accounts for natural variation in body types and development stages. If your BMI is in this range, you're considered healthy weight. However, remember that BMI is just a screening tool, not a complete picture of health. Your overall wellbeing includes nutrition, physical activity, sleep, mental health, and how you feel in your body—not just a number on a chart.
Teens' bodies are actively growing and developing, with major changes in height, weight, body composition, and hormone levels happening throughout adolescence. A BMI of 22 might be healthy for an 18-year-old but could indicate overweight for a 13-year-old. BMI percentiles account for these age-specific and sex-specific differences by comparing your BMI to other teens of the same age and biological sex, making the assessment developmentally appropriate. Adult BMI categories aren't accurate for teenagers because they don't account for ongoing growth.
Not necessarily. For growing teens, the goal is usually not weight loss but rather maintaining current weight while continuing to grow taller, which naturally brings BMI down over time. Focus on healthy behaviors—balanced nutrition, regular physical activity, adequate sleep—rather than weight loss. Dieting and calorie restriction during adolescence can backfire, leading to weight gain (not loss) long-term and significantly increasing eating disorder risk. Always consult with a healthcare provider before making significant changes, and prioritize overall health over weight.
Yes. BMI doesn't distinguish between muscle and fat, so teens with high muscle mass from sports may have elevated BMI despite being healthy. Athletes in sports like football, wrestling, gymnastics, or weightlifting often have BMI in the overweight or obese range due to muscle, not excess fat. If you're athletic, active, eating well, have normal blood pressure and lab results, and feel healthy, an elevated BMI likely reflects muscle rather than health concerns. Your doctor can assess body composition more accurately through physical examination.
Please reach out for help. Body image struggles and disordered eating are common but serious—they don't get better on their own and early intervention dramatically improves outcomes. Talk to a parent, school counselor, trusted adult, or healthcare provider. Call the National Eating Disorders Association Helpline at 1-800-931-2237 or text "NEDA" to 741741 for immediate support. You deserve to feel comfortable in your body and have a peaceful relationship with food. Professional support can help you develop healthier coping strategies and improve both physical and mental health.
Healthcare providers typically check BMI annually at routine physical exams, which is sufficient for monitoring growth patterns over time. Checking BMI more frequently at home isn't necessary and can increase anxiety and body preoccupation. If you're working on health goals with medical supervision, your provider may recommend more frequent monitoring. Focus your daily energy on healthy behaviors (eating balanced meals, moving your body joyfully, getting adequate sleep) rather than frequent weight or BMI checking, which can fuel obsessive thinking.
Weight gain during puberty is normal, healthy, and necessary for development. Girls typically gain 15-55 pounds during puberty, with increased body fat supporting reproductive health and hormone production. Boys gain 15-65 pounds, primarily muscle mass. These changes are biologically programmed—not something you need to prevent or reverse. The timing and pattern vary widely among individuals. Some teens experience gradual changes while others have rapid growth spurts. Your body knows what it needs to do for healthy development. Restrictive eating during puberty can interfere with normal growth, delay sexual maturation, and harm bone development.
Yes, many teens feel awkward or uncomfortable as their bodies change during puberty—you're not alone. Your brain needs time to adjust to your new body size and shape. These feelings often improve as you become accustomed to your changing appearance and as puberty completes. However, if body discomfort persists, intensifies, or significantly impacts your daily life, mental health, or eating habits, professional support can help. Therapists specializing in adolescent development and body image can provide tools to improve body acceptance and develop healthy coping strategies during this challenging transition.
