Last updated on January 1, 2026
Question:
Hello Sir,
I am writing to respectfully request your opinion on my final adult height potential based on the following key data points.
My Data:
- Current Age/Height: 15.5 years old, 5’8.25″
- Puberty Onset: Potentially started around 12.0-12.5 years, but I’m unsure.
- Peak Growth Rate: 4 inches per year (13.0 to 14.0 years)
- Voice Deepening: Began at 13.9 years
- Tanner Now: 4.0-4.1 (3.2-4.9 range)
- Body Composition: Very low weight/fat (1st-5th percentile), potentially delaying growth plate closure from what I’ve heard.
- 13.0: 5’0, 14: 5’4, 15: 5’7, 15.5: 5’8.25
My growth rate is currently decelerating, but still ongoing (2.5 inches a year). Given my current height and the potential for a prolonged growth period due to the low-weight factor, I would be grateful for your estimate of my likely final adult height range and whether I could potentially achieve a final height of 5’11. Thank you.
Thank you for your time and expertise.
Answer:
You mention that your weight and body fat ratio are low, but you never specify what they are. Your current weight is an essential piece of information in the calculators used to estimate your final height (Predicting Your Adult Height).
Based on your growth, it appears you are either in late-stage 3 or early-stage 4, which agrees with the calculator. I can’t provide a more precise estimate without more information. Boys tend to grow 1 to 3 inches during their two-year time in stage 4. Therefore, you will likely be between 5’9 and 6’0. Where you will fall in that range would be hard to predict.
Being significantly underweight for your height does impact development. After all, it is hard for the body to grow when there is not enough fuel and material to allow development. Low body fat often leads to delayed puberty. It can also affect your immune system, cognitive abilities, and overall energy. A good body-fat ratio is between 10 and 20%.
Question:
Hello Minister,
I believe my weight is 107 lb now, 105 lb at 15.0, 90 lb at 14, and 76 lb at 13. I definitely understand that being underweight impacts cognition, growth, and other things. Still, I’m also confused because despite being underweight, I’m performing at the top of my classes, have been successfully running for my school’s track and field team, and my growth looks normal, so it’s pretty weird; it seems that it possibly hasn’t had a significant effect on me and instead I may be genetically predisposed to being thin. Also, I’m not sure what my height is right now, but I’m pretty sure it’s between 5’8 and 5’8.25, so my growth is 2 to 2.5 inches a year. Does that line up more with a little after stage 4 (4-4.1) or right before (3.9-4.0)? Thank you so much for your assistance, and I look forward to your response.
Answer:
At 107 lbs, that gives you a BMI of 16.3, which is in the underweight range. A typical healthy range for an athletic male is between 18.5 and 24.9. However, endurance athletes, such as runners, can have a BMI less than 18 and still be healthy. So while low, it doesn’t sound like you are in the malnourished range.
Have you done a body fat assessment? If so, what value do you currently have?
Try using the “KGH Method” to get an estimate of your final adult height. I suspect you’ll get an answer between 5’10 and 5’11.
Question:
Hello,
I have not professionally done one, but using the waist-to-height ratio method, I have a body fat of 16.7% (DEXA) and 13.25% (Calipers), which aligns with your healthy range, which explains why I haven’t felt many negative downsides despite being underweight.
Upon re-measuring, I’ve gotten different results, but they generally range from 10-17% using just waist and height. Based on this, how is my overall growth impacted?
Using your BMI calculator, it’s 11.3%, and using the waist calculator, it’s 9-10%, so I’d say my body fat is probably between 9-13%. Based on this estimate, has my low weight impacted my growth, or does my potentially healthy body fat keep me safe?
Many thanks for your assistance.
Answer:
Given that your body fat is above the minimum, if barely, it would not impact your development. However, be aware that you basically don’t have reserves. If you fall ill, your body fat may drop too low, affecting your recovery from the illness and temporarily impacting your growth. Once you get back to normal, your body will make up for lost time. Therefore, I don’t think you have any reason to be concerned.