Arms are every fitness buff’s pride and joy. The ‘Show’ muscles as they call it. The ‘gunz’ or the ‘Pythons’ in gym bro lingo.
If you have puny arms, you are a weakling. Period. Your 600 lb. deadlift means nothing.
But, if you have bigger arms, you automatically qualify for a spot in the hall of fame, regardless of your 1 Rep Max compound lifts.
The opposite sex will go weak in their knees. Your frenemies will quiver in fear as you walk the neighborhood.
That said, how many inches do them arms need to be and when are arms considered big?
Haven’t you ever wondered about how many more inches do you need to gain on your arms before you are officially awarded a big Bicep ‘Knighthood’?
Today, we are going to show you exactly that. So stay tuned.
Understanding the muscles that make the ‘Arms’
Arms are divided into two parts, anatomically speaking. We don’t blame you for thinking that it was only the bicep. It is probably the most popular muscle amongst fitness buffs universally. One that has its own emoji.
But your arms are made up of the upper arm and the forearm. The upper arm comprises of the anterior compartment and the posterior compartment, and runs from your shoulders to your elbow.
The part below the elbow is the forearm which is also made up of anterior and posterior compartments. Each compartment has multiple muscles. In this article, we are going to focus solely on the upper arm, which is made up of the Bicep and the Triceps.
The Bicep – Functions & Aesthetics
Picture this. You are walking out of the gym with the best pump you’ve had all week. Someone asks you to flex your muscles. Chances are that you are going to instinctively give them a glorious ‘Front Double Bicep’.
That’s because the Bicep or the ‘Biceps brachii’ is the de facto show muscle. But beyond popping out of your t-shirt, it performs some very important functions.
It allows you to flex your elbow and supinate the forearm, two physiologically-critical functional movements. Flexion is when you move your wrist towards your shoulder, like the bicep curl. Supination and pronation is when you move your arm inwards towards your waist and outwards again.
In addition to this, it also helps the shoulders to flex the humerus, especially while moving it anteriorly.
The Biceps is made up of two heads, the long head and the short head. The short head of the bicep is located on the ‘inside’ of the arm, while the long head is located more laterally. When you flex your bicep, the short head or the medially located part will determine the thickness, while the long head will determine the bicep height, commonly called ‘The Peak’.
There is also the Bicep brachialis which lies hidden under the long head and is very underrated for what it can do aesthetically. It ‘pushes’ the long head of the bicep upwards making it appear taller, or giving you the famed bicep peak.
This does depend to an extent on your genetic bicep insertions. Some people are born with longer bicep bellies which make their biceps appear thicker, but shorter. A case in point is bodybuilder Sergio Olivia. Others are gifted with shorter bicep bellies, which makes their peak appear much taller. A prime example would be Arnie Schwarzenegger.
To increase the size of your biceps, you have to focus on both the bicep heads and the brachialis. We will touch on this when we cover exercises to increase bicep size.
The Triceps – Functionality & Aesthetics
The Triceps make up 66% of the arm. That’s 2/3rd of the arm size. So, if you are guilty of hyper-focusing on the biceps, you know why your arms are scrawny to begin with.
The Triceps is associated with some of the most important functional movements. At the forefront is extension of the elbow joint, for which it works in synergy with the biceps. At the shoulder joint, the triceps and the lateral muscles work together to help you move your arm towards your body.
Come workout time, the triceps are an important secondary muscle involved in all your push exercises. That includes the chest press, the shoulder press and power moves like the clean and jerk.
Aesthetically, it is very important to build thick triceps if you are looking to increase arm size. The Triceps are made up of three muscle heads, which are the lateral head, the medial head and the long head.
Just like the biceps, you have to ensure that you hit all three to add size to your arms.
The Average Arm Size for Men & Women
Before we begin to crunch numbers, let’s take a look at some average arm sizes according to one’s age and sex. These numbers may vary greatly in people who are chemically enhanced mind you. But if you are a regular joe drinking their protein shakes and creatine, then chances are that your arm size is close to this.
Female Age – Average Bicep Size
- 20-29 —————- 12.4
- 30-39 —————-12.9
- 40-49—————–12.9
- 50-59—————–12.9
- 60-69—————–12.7
- 70-79—————–12.6
Men Age – Average Bicep Size
- 20-29—————-13.6
- 30-39—————-13.8
- 40-49—————-13.9
- 50-59—————13.5
- 60-69—————13.4
- 70-79—————12.9
As you can see, the average numbers are nothing to write home about. If you are even at 14”, your arms are probably considered bigger than most of the population. But if you lift, your comparison is no longer with mere mortals, is it?
Here are some more interesting numbers, this time from the bodybuilding universe.
- Ronnie Coleman – 24.01”
- Frank Zane – 18” (Rumored to be 17”)
- Arnold Schwarzenegger – 21.65” (Rumored to be 19”)
- Flex Wheeler – 20.86”
- Jay Cutler – 22.44”
We know what you are thinking. These are guys who probably had more chemicals in their system than in a pharmaceutical factory, when these measurements were taken. Besides, don’t discount the fact that bodybuilders would frequently exaggerate measurements to ‘psyche’ out their primary opponents.
Also, arm size measurement is a primitive science. Talk about health markers and we boast of Dexa scans and DNA mapping. But when it comes to measuring the size of one’s arms, we grab that rudimentary tape. There are several parameters that can help inflate those numbers. So, take that with as big a grain of salt as you’d want to.
That segues into the question at hand though.
What Size Arms Should You Have?
To be honest, your arm size is considered big as long as it ‘looks big on you’ and is in symmetry with the rest of your body.
For instance, a bodybuilder who’s shorter than 5’10 might appear to have huge arms even if they are 15-16”. But for someone who’s 6’4, that same size might seem small. Symmetry and perspectives are more important than they are believed to be.
Look at gymnasts. Some of the best gymnasts are shorter than 5’6. But their arms look huge and muscular. We are pretty sure that if you’d tape them, they’d not be more than 14-16”.
Symmetry in fact is the most underrated aspect of bodybuilding. Given that each one of us will respond differently to continual stress provided by exercise, to nutrition and even to rest. But here’s a universal definition of the perfect symmetry for the male physique.
- Neck – 17”
- Upper Arms – 17” Cold (No Pumps and at least 10-12 hours since the last workout)
- Calves – 17”
We can assume that most of us are nowhere close to those numbers. So, here’s another ballpark chart that will let you put a finger on your current arm size and how it fares in comparison with the rest of the fitness population.
- 11-12” – Congratulations. Your arms are smaller than the average female.
- 13-14” – You are an average joe, with a long way to go
- 15-16” – You are on the path to glory. But if you haven’t hit your genetic potential yet, then you might be able to break that glass ceiling with some targeted training
- 17-18” – You are one of the rare immortals.
- 19-20” – This is officially the big arms zone. Your guns are huge and flaunt them with pride
- 21” – You are a genetic freak.
Does that make it easier to break down? Which category do you fall into? Don’t get hung up over those numbers yet. We have some factors to present which can affect these numbers positively or the other way.
Factors that can affect arm size
Chemical Enhancement – Steeve Reeves is the god of symmetry. His arms at his peak were said to be 18.5” (plus or minus one or two inches). The next person who came close to that was Zane. But if you notice, bicep sizes have consistently increased over the years as chemical cocktails became mainstream in professional bodybuilding. Ronnie Coleman was genetically gifted for sure. But 24 inch arms don’t come that easy and would considered super human! If Arnie’s arms were 19” in reality, with all that DBol, picture what a naturally trained guy can achieve.
Fat Percentage – When we talk about arms, we mean lean muscle. Someone at 35% bodyfat could also boast of 20 inch arms. But if you peel the body fat away, the actual muscle tissue under it might be just 12-13”. So, when someone speaks arm size, check body composition to know how much of it is really muscle.
Measuring Tape – Ellington Darden, the famous fitness guru from the 80s would often scoff at the arm measurements of pro bodybuilders from the golden era. He claimed that the numbers were always inflated. To get accurate measurements, or at least close to it, you need to have a measuring tape that’s dry, not pliable, doesn’t stretch and does not slip when placed on your body. We will also speak about measurement technique in a bit.
Synthol – This is one of the banes of modern technology. People can use chemicals like synthol to artificially inflate arm size. Sadly, this looks nothing like real muscle tissue should. In fact, in all probability, it will look comical because of disproportionate symmetry. A case in point is Moustafa Ismail, the ex-Guinness Book of Records holder for the biggest arm size at 31”. A look at his pictures will tell you how messed up that is. FYI, the Guinness Book no longer accepts claims for arm size.
Bone Structure – The size of your wrist is an accurate representation of how big your arms can get naturally with training. The rule of thumb is that the thinner the bone structure, smaller the arms. So, if your wrist circumference is 7” hypothetically and your gym buddy has 8” wrists, his arms will naturally be bigger than yours.
Cosmetic Enhancement – Just like boobs and butts, silicone bicep insertions are on the rise. Sigh!
How to increase inches to your arms size
All said and done, how do add to your arm size? As we said at the onset, to add size to your arms, you need to work on the entire upper arm. Target every single muscle head, get your nutrition in order and you will notice that your arms start to magically grow in size.
Here’s some help.
Exercises to achieve bigger Arm size

This is not an exhaustive list by far. If you look up on the internet, you’ll find hundreds of arm workout plans with tons of variations. The good thing is, you’ll never run out of exercises to try. Hence, there will never be boredom setting in.
- Standing Bicep Barbell Curl – Targets the long head of the biceps. Arnold called this the ‘Granddaddy of all Arm Exercises’.
- Seated Dumbbell Curls
- Hammer Curls – Targets the brachialis and your forearm. Did you know that increasing your forearm size can also help you increase your arm size?
- Preacher Curls – More isolation
- Chin Ups – Can Add weight. It’s a terrific compound move.
- Dips – Targets all three triceps heads
- Skull Crushers – Long head and the lateral head
- Kickbacks
The above routine targets all-round arm development. Like we said, it’s not the be-all, end-all. But it’s a good place to begin with.
Focusing on Hypertrophy for bicep size
The thing with arms is that they are such a critical secondary muscle group that you are automatically working them out whenever you hit any upper body muscle group. So, if your arm size is not growing despite having the best arm workout schedule, you might want to re-evaluate your overall workout plan.
Here are some ground rules.
- Work your arms 2-3 times per week only
- Ensure that you hit at least 8-14 sets in total volume
- 6-8 reps per set is the sweet spot for most. You can go to 12 reps if need be. Some bodybuilders recommend going beyond failure. But that’s again goal specific.
- 90-seconds of rest between sets. This does not apply for supersets. But don’t spend 3 minutes lollygagging in front of the mirror after every set.
- 85% of your 1RM is the weight you should aim for.
- At least 48-hours of rest between upper body workouts
Do you need a separate arm day for bigger arms?
That depends on your goals. But it won’t harm you to have a separate arm training day, as long as you are not overworking them. In fact, it might help you a fair bit, especially if you are struggling to add size.
Some people add a couple of arms exercises at the end of the major muscle group they are targeting on the day. For instance, if they are hitting chest, they add two sets of triceps towards the end. If they are hitting back, they add a couple of sets of bicep curls towards the end.
Does this work? It might.
But there is a possibility that you might not be able to go at full steam because your arms are already exhausted from all that heavy lifting. So, adding a separate arm day allows you to train them fresh and add some great isolation moves, which will allow you to focus on concentration and form.
If you are training your upper body thrice a week, make one of these days an arms day. So, you get two days of indirect arm work and one day of direct arm training.
Measuring your arm size the right way
Last but not the least, let’s talk about measuring your arm the right way.
Measure your arms cold when you have no pumps and your last workout was at least 12-hours ago.
- Flex your biceps.
- Grab a dry measuring tape and wrap it around the thickest part of the arms, which is generally around the center, between the elbow and the shoulder.
- The tape must be wrapped tight enough so that it doesn’t sag. But not tight enough to bite into the skin.
- It must be straight, not bent.
- Now place the end as close as its possible to the 1” mark aligning both the side edges.
If done right, this number is your upper arm size.
Wrapping Up
So after reading this post are you still pondering of what bicep size is considered big?
Rather than focusing solely on your arm size, symmetry might be a better goal to aim for. Sure, if your arms are your weak spot, you can pay more attention by targeting all muscle heads in a separate workout.
But in comparison to the rest of the muscle groups, your arms are pretty small. Follow the basics and you will see results.