The biceps muscles are an important area for many people because they’re a highly visible body part (especially compared to the triceps, which are situated on the back of the arm).
A lot of people also get preoccupied with whether they have a normal bicep size or not. They often want to compare their own arm measurement with those of other people.
With these tendencies in mind, the following guide uses real-life statistics to answer the question that you’re probably curious about: Is having 9 inch biceps good? Or is it a measurement that I should be concerned about?
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Are 9 inch biceps small?
Let’s cut to the case; are 9 inch biceps small or not?
Yes, in the vast majority of cases, 9 inch biceps are very small. Whether or not having 9 inch arms is bad depends on whether such a circumference causes you to have an excessively low BMI. 
Since being underweight can cause various health problems to arise, you should talk with your doctor if your BMI is too low so that you can figure out how to safely and effectively increase your body mass.
The exception to a 9 inch bicep circumference being bad is if you or your child is still growing.
Specifically, boys and girls aged 10-12 usually have 9” arms or thereabouts. So at some point, just about everyone will go through a stage where they have 9” biceps.
Of course, retaining your 9 in arms as you get into adolescence and adulthood can be problematic if it coincides with an unhealthily low body mass.
How about 9.5 inch biceps?
When your arms are very skinny, adding even half an inch to their circumference can make a noticeable size difference.
The issue is that 9.5 inch biceps are still small if you’re an adult because, as mentioned, such a size is typical for children aged 10-12. 
Of course, if you’re seeking to grow your arms and have gone from 9 inch to 9.5 inch arms, then that’s definitely an achievement.
If you want to build upper arms of normal size, however, then make sure to check out the next section for some helpful bicep-building tricep-toning tips.
How can you surpass your 9 inch arms?
Now that you know that 9 inch arms are small, it’s time to learn what you can do to increase your arms in order to make them a normal, healthy size.
Increase your training volume
Training volume, which is to say the amount of “work” that you perform for each muscle group (usually thought of as reps x sets x weight), is the primary driver of muscle hypertrophy.
Although you might not desire to be big and muscular, everyone needs at least some muscle mass on their arms.
Training your biceps and triceps with weights will help them to become thicker and more toned.
You’ll also make your arms stronger and more capable of performing everyday tasks with ease; no longer will your puny arms struggle to carry those grocery bags!
Now, increasing your training volume doesn’t mean living in the weight room or even getting a gym membership, for that matter.
Performing 3-4 sets of bicep and tricep work 1-2 times per week is a great place to start. Just make sure to focus on your compound exercises as well (pulldowns, rows, shoulder press, etc.) because such exercises are a highly efficient way to train multiple muscle groups at once.
Consume more calories
Consuming enough calories to steadily increase your body weight will give you more energy and make you feel stronger when you exercise.
In contrast, if you undereat, then you might not feel like working out at all. Skipped workouts, in turn, will lead to stagnant physique development and low motivation.
Instead, eat in a calorie surplus so that your body can build new muscle tissue. It’s normal to gain some body fat as well, especially if you’re starting from a very skinny physique.
Within your diet, it’s important to eat enough protein so that your body can accumulate new muscle tissue.  Foods such as meat, fish, dairy, and eggs are protein-rich and are also packed with other nutrients. Additionally, you can get plenty of protein from plant-based sources like beans and lentils.
Train and eat consistently
Eating in a calorie surplus and hitting the gym for a week is all well and good, but if you don’t train and eat consistently, then you won’t see much physique progress.
Since 9 inch biceps are small, to begin with, you can see pretty rapid progress in the first month of your program.
Working out with weights 2-3 times per week is a great place to start. Even high-performing athletes don’t lift every day, so it’s not like you’ll speed up your results by exercising more frequently, especially if you’re new to resistance training.
The verdict: Should you be worried about having 9 inch biceps?
Whether or not you should worry about your 9 inch biceps depends mainly on your age and height.
For example, if you or your child is still developing, then, depending on their age, 9 inch arms could be normal. As mentioned, boys and girls aged 10-12 typically have 9” arms or 9.5” arms.
On the other hand, if you’re an adult man or woman of a typical height, then 9 in biceps are a strong indication that you’re underweight and should talk to your doctor.
- NHS website. (2021, November 18). Underweight adults. Nhs.Uk. https://www.nhs.uk/live-well/healthy-weight/advice-for-underweight-adults/
- Centers for Disease Control and Prevention. (2021, January). Anthropometric Reference Data for Children and Adults: United States, 2015–2018 (National Center for Health Statistics). United States Department of Health and Human Services. https://www.cdc.gov/nchs/data/series/sr_03/sr03-046-508.pdf
- Michelle Neff, Michigan State University Extension. (2018, September 20). Know the importance of muscles and protein. MSU Extension. https://www.canr.msu.edu/news/know_the_importance_of_muscles_and_protein