Once upon a time, the t-shirt and the undershirt were close bosom buddies. More than that–they used to be the same thing.

Nowadays, though, the t-shirt vs. undershirt debate has taken root.

It’s not just a matter of semantics. These days, the two shirts are entirely different animals.

Questions You May Be Asking

This article will answer the following questions:

  • How is a t-shirt different from an undershirt?
  • Should I wear a t-shirt as an undershirt?
  • Can I wear an undershirt as a t-shirt?
  • Should I wear a t-shirt or undershirt?

What Is The Difference Between A T-Shirt and Undershirt?

In simple terms, a t-shirt is outerwear. An undershirt is underwear.

A well designed and properly fitting undershirt should not be worn as a t-shirt. Similarly, a t-shirt can't function as an ideal undershirt.

To provide an anology, it would be like wearing dress shoes to run a marathon.

While you can run in dress shoes, you will run much faster and more comfortably in running shoes -- shoes specificaly designed for the purpose of running.

It's the same with t-shirts and undershirts.

Before you invest in an undershirt, you should know what you’re signing up for.

Below are the key differences between a t-shirt and an undershirt that you need to know before you get dressed for work.

Be sure to check out our T-Shirt -vs- Undershirt Infographic at the end of this article!

A Brief History of T-shirts and Undershirts

To better understand the difference between t-shirts and undershirts, it helps to take a quick look at the history of the two.

T-shirts originated in the late 19th century, after the Industrial Revolution. Back in the day, workers would cut their jumpsuits in half so that they could stay cool at work during the warmer months of the year.

The first-ever manufactured t-shirt came into being around 1913 when the United States Navy began issuing t-shirts as standard undershirts.

The term “t-shirt” joined the English dictionary thanks to F. Scott Fitzgerald’s novel This Side of Paradise.

T-shirts vs Undershirts: T-shirts were originally warn in the U.S. Navy

T-shirts didn’t become a wardrobe staple in their own right until 1950. Up until that point, t-shirts were worn exclusively as undershirts.

Then came Marlon Brando in A Streetcar Named Desire and James Dean in Rebel Without a Cause, both sporting t-shirts as standalone garments.

It was a striking political statement because at the time, wearing just a t-shirt was like walking out the door in just your underwear.

As t-shirts took off as everyday garments and began being printed with slogans, they cut a separate path from undershirts, which remained an undergarment a la underwear.

9 Key Differences Between T-Shirts and Undershirts

That history should help illuminate a few key differences between your average t-shirt and an undershirt.

These days, the two might look the same, but there’s actually a number of significant differences between them.

Here are nine key differences between these two garments, affecting how, when, and where you should wear them.

1. Wearability

First thing's first: wearability.

T-shirts and undershirts may have started out as the same thing, but they’re not anymore.

Undershirts originated from the union suit, which men used to protect their skin from itchy clothing and to keep their clothes from becoming sweaty and smelly.

Eventually, the union suit was split in two (thus the origin of long johns) but the appeal of the idea never went away.

Undershirts are like underpants, which are exactly what the name implies. Undershirts=under your shirt, just like underpants=under your pants.

So, much like you wouldn’t go outside with your underwear out for the world to see, you shouldn’t go outside wearing an undershirt like a t-shirt.

A t-shirt, on the other hand, is meant to be appreciated in all its James Dean rebellion glory. You can wear a t-shirt just like a normal shirt.

In some rare cases it can technically double as an undershirt, but these days, it’s MUCH less comfortable to wear a t-shirt instead of an actual undershirt when the occasion demands it.

2. Thick and Thin

That’s because of a thickness difference between the two shirts.

Undershirts are made to be worn under another shirt. These days, you usually see undershirts worn under collared work shirts and ties (a suit is a separate matter altogether).

They’re much thinner and lighter than t-shirts. And because they’re meant to be worn under your actual shirt, they normally only come in white, grey, black, and nude (tan).

T-shirts are a different story. Since they’re made to be worn as a shirt on their own, they’re thicker than undershirts. They also come in all sorts of colors with a variety of designs for you to choose from.

3. To Stink or Not to Stink

This brings us to our next question: to stink, or not to stink?

You see, undershirts today are primarily worn underneath a collared work shirt. There are two reasons for this.

The first is coverage. You don’t want your nipples awkwardly showing through your shirt in a meeting.

The second is the stink. Specifically, to prevent it. When you move and sweat during the day (even a little bit of sweat) an undershirt is there to keep sweat from soaking into your work shirt.

T-shirts, on the other hand, are worn like any old shirt. They absorb sweat the way any old shirt does.

So, there is a distinct possibility that your t-shirt could actually stink by the end of the day (depending on what you do in the course of a day).

4. Shirt Length

Another critical difference between t-shirts and undershirts is the length of the shirt in question.

Since an undershirt is designed to be worn underneath a regular collared shirt, it’s longer than most regular t-shirts.

This is for a purely practical reason: since an undershirt is designed to go unnoticed, it has to stay tucked into your pants.

So, having a longer undershirt prevents the shirt from coming loose every time that you move.

A t-shirt, on the other hand, is more variable. As a rule, they’re not as long as undershirts since most people prefer a shorter cut for their shirts so they can be worn untucked.

That way, you don’t end up sitting on your t-shirt all day.

5. Sleeve Length

The same basic logic applies to the sleeve length.

An undershirt is intended to go unnoticed underneath your clothes. For this reason, the sleeves are generally shorter than a t-shirt – you don’t want the lines of your undershirt showing through your sleeves.

This makes it possible to wear an undershirt under a long-sleeved or short-sleeved shirt.

The sleeves also tend to be more fitted than a regular t-shirt.

With a t-shirt, on the other hand, the rules are much looser. Sleeves tend to be longer and looser for a more comfortable fit and a more organic cut.

6. Find the Right Fit

And speaking of fit, the fit between a t-shirt and an undershirt is also quite different.

The entire point of an undershirt is that it’s, well, under your clothes. But you don’t want to walk into work looking like you’re prepared for the Arctic (or, at least, wearing another shirt underneath your work shirt).

So, undershirts are much more fitted than most t-shirts (not all t-shirts, but most).

The idea is that the fabric won’t show through, even if your regular shirt has a rather fitted cut.

7. Keep Cool vs. Look Cool

It might sound counterintuitive, but wearing extra clothes can actually help you cool down (at least, if one of those layers is your undershirt).

In order to maintain a consistent core body temperature, the human body sends blood to the surface of the skin and sweats. As the sweat evaporates, heat evaporates off the body and helps cool you down.

The key component here is evaporating sweat. If your sweat doesn’t have anywhere to wick off, you won’t be able to get any cooler.

This is where an undershirt can help. It helps wick moisture off of your body and keep it from settling on your clothes.

This also helps you keep sweat off of your clothes, avoiding those dreaded pit stains.

8. Collared

The collar situation is another point of disparity.

As a rule, undershirts have a deep V-neck. There are other options available for those who don’t like such a plunging neckline under their clothes, but the V-neck isn’t for aesthetics.

Like most features of the undershirt, the V-neck is there because it helps the shirt go undetected under your clothes. You can get the benefit of an undershirt without anyone actually knowing you’re wearing an extra layer under there.

T-shirts vary widely depending on style and personal preference. Since it’s a shirt worn on its own, the choice is yours. You could rock a crew neck, or you could go all-in for a V-neck.

9. Underwear vs. Outerwear

Finally, in case the message hasn’t sunk in yet: the difference between an undershirt and a t-shirt is the difference between underwear and outerwear.

An undershirt is your undercover support system. It adds a layer of sophistication (and some sweat-wicking action) to keep you cool as a cucumber, even in high-pressure situations.

A t-shirt is an all-around hang out shirt. It can be dressed up or down, depending on the shirt and how you wear it, but it’s a shirt in its own right. It’s meant to be viewed and appreciated by the world (or, at least, those around you who appreciate your taste in t-shirts).

The Difference Between T-Shirts & Undershirts Infographic

We distilled the above 9 t-shirt vs undershirt differences down even further!

The infographic below shows the Top 7 ways undershirts and t-shirts are different.

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T-shirt vs Undershirt | Top 7 Differences

Top 7 Differences Between Undershirts vs T-Shirts

  • Undershirts should be thinner -- to keep you cool.
  • T-shirts are thicker so they can be worn by themselves.
  • Undershirts provide a layer of defence between your body and your shirt. They will protect your shirts from sweat, stains, & odors.
  • T-shirts are mostly worn alone, coming in direct contact with sweat, body oils, and odors. They have to be washed after every wear.
  • Undershirts are designed longer so they stay tucked.
  • T-shirts are shorter, so they can be worn untucked, without being too long.
  • Undershirts have shorter sleeves, so they can be worn under short-sleeve shirts as well as long sleeve shirts.
  • T-shirt sleeves are longer since they are worn by themselves.
  • Undershirts will have deeper v-necks so the collar stays hidden with an open collar.
  • T-shirts have a shallower v-neck. They offer style, while keeping chest hair covered.
  • Undershirts should be close fitting or fitted so they don't add extra bulk under your clothes.
  • T-shirts are generally looser fitting to accommodate different body styles.
  • Undershirts are underwear.
  • T-shirts are outerwear.

Ordering the Right Undershirt for the Job

When it comes to the question of t-shirt vs. undershirt, it’s a question of what you’re after.

Do you need something to keep you cool and collected underneath your work clothes? If so, you need an undershirt.

Do you need a shirt to look cool, whether you’re at a summer barbecue, a concert, or walking around town? If so, you need a t-shirt.

If you’re in the business of sophistication, good news. We offer high-quality Made in USA undershirts for tastemakers like you.

Check out our selection to find the perfect undershirt for the job.