Anyone with a 20 inch neck has a very large neck circumference. So, of course, a 20 inch neck is extremely big. The better question is this: What does a 20 inch neck look like in real life?
And also, what are the pros and cons of having a 20" neck? Does having a neck that thick negatively affect your health? Let's find out.
See How Your Neck Compares:
How big is a 20 inch neck?
So, just how big is a 20 inch neck? Based on the data, a 20 inch neck is absolutely huge because it's around 5 inches bigger than average. That's some serious neck girth.
It suffices to say that most people will never have a 20" neck unless they get ridiculously obese. In other words, even if you train your neck directly with resistance for a number of years, it's unlikely to ever measure a tape-tearing 20 inches.
One of the benefits of having a 20 inch neck (or, more specifically, a strong neck), especially if you're an athlete, is that it can decrease your risk of concussion.  Now, you definitely don't need a 20 in neck to have a strong neck. And as you'll see later on, having a 20" neck likely comes with some negative health consequences.
What shirt size is a 20 inch neck?
In most clothing brands that I researched, a 20 inch neck was equal to a size 4 XL or 5 XL. Some clothing brands didn't even make shirts that accommodated a 20 inch neck.
Also, keep in mind that if you have a 20" neck, you'll want to choose a collar size that's slightly bigger so that you have enough breathing room. Many guys like their t-shirts skin-tight to show off their upper body muscles, but you definitely don't want to get choked by the collar on your shirt!
If your 20 inch or 20.5 inch neck is way bigger than the rest of your upper body (relatively speaking), then you'll likely need to get custom-fit shirts to accommodate your unusually large neck.
Who actually has a 20 inch neck?
Take a look at these muscle machines if you want to see what a 20 inch neck looks like.
Brad Arbic is a powerlifter who has a verified 20 inch neck. It seems like he trains his neck directly, which would definitely explain some of the size. But his thick build and colossal body weight (300 lbs is pretty heavy) likely explain how he was able to build a legit 20" neck.
His video is a particularly good watch because it shows how well (and how fast) the neck responds to training. Brad pumped up his neck by around 2 inches with just a few minutes of neck training.
Sure, this was a temporary size increase, but it just goes to show that the neck responds to training like any other body part. So don't think that the only way to build your neck is to gain weight; direct training is your best bet for sculpting a thick 20 in neck.
If you ever needed evidence that having a thick neck makes you look more intimidating, look no further than Mike Tyson. Iron Mike was a fan of wrestler bridges for building his neck, which is definitely not an exercise for beginners.
In boxing terms, Tyson had a phenomenal chin, and his massive 20 inch neck may well have had something to do with his incredible punch resistance. After all, when you can brace for a punch, your head won't get snapped back as far, which likely reduces your chance of getting knocked out.
Since Mike Tyson was obviously an incredibly gifted boxer, it just goes to show how unrealistic building a 20" neck is for the average person. Sorry, but chances are, you're just not on Tyson's level. I'm certainly not.
Mike "The Machine" Bruce
Mike "The Machine" Bruce has a big physique, but it's his truly colossal 20 inch neck that really catches your attention.
Known for his incredible feats of strength, such as a 300 lb neck raise and 400 lb sit-ups, Bruce is an incredible athlete who shows that strength is about more than just the "Big 3" lifts.
Bruce is also a grappling, wrestling, judo, and kickboxing champion—sports in which having a thick neck will definitely improve your performance.
If you want to build your own neck for performance or for aesthetics, then Mike's channel and website are definitely a great resource that you should explore.
How to get a 20 inch neck
One thing's for certain: If you want to build a muscular 20 inch neck, then you're going to need to train your neck directly. Sure, there are people with genetically big necks. But genetics alone can't explain a lean 20" neck.
To get your neck anywhere near the 20 inch mark, you'll need to utilize high rep training. Stick with sets of 20-30 reps most of the time. You don't want to do low reps for your neck training because a) it could be dangerous and b) the range of motion is so small on neck exercises that you practically have to do high reps to get enough time under tension.
Also, train your neck from every angle. Flexions and extensions will build most of your mass, but also do your side neck raises and rotations so that you can stimulate the widest possible variety of neck muscle fibers.
Additionally, you'll very likely need to gain some weight (unless you're already big) if you want to develop a genuine 20" neck. You don't need to get fat, but increasing your body mass will definitely help to increase your circumference measurements—neck size most definitely included.
What are the downsides of having a 20 inch neck?
Earlier I mentioned how having a big neck can help to protect against concussions. Well, that study looked at neck strength rather than neck size. So it's not like you need to have an absolutely massive neck to have a strong neck.
Of course, all else being equal, a bigger neck is a stronger neck because large muscles have more force output potential.
Still, there's a point of diminishing returns when it comes to building the neck. To get your neck to 20 inches, you need to use progressively heavier weights which, like it or not, will increase your injury risk, which is especially undesirable for crucial body parts like the neck and spine.
Additionally, having a thick neck increases your risk of developing sleep apnea, which is a very dangerous health condition.  For this reason, it's probably not worth building a 20 in neck—there just aren't enough people with muscular 20 inch necks to say that having a neck that thick is safe.
Conclusion: Should you try to build a 20" neck or not?
Honestly? Most people won't be able to build a 20" neck without getting fat. And when you consider that both obesity and neck circumference are risk factors for sleep apnea, it seems like a bad idea to aim for a 20 inch neck or a 20.5 inch neck.
Remember, you can have a strong and muscular neck while having it measure much less than 20 inches. I get that many people want to feel special and be more muscular than average, but you also need to consider the downsides of building your neck to a frankly unnatural size.
- Collins, C. L., Fletcher, E. N., Fields, S. K., Kluchurosky, L., Rohrkemper, M. K., Comstock, R. D., & Cantu, R. C. (2014). Neck Strength: A Protective Factor Reducing Risk for Concussion in High School Sports. The Journal of Primary Prevention, 35(5), 309–319. https://doi.org/10.1007/s10935-014-0355-2
- Sleep Apnea - Causes and Risk Factors | NHLBI, NIH. (2022, March 24). NHLBI. https://www.nhlbi.nih.gov/health/sleep-apnea/causes