The Differences between Heavyweight and Lightweight T-Shirts

SANVT Journal

T-shirts are a wardrobe essential that everyone owns but despite their status as a ‘basic’ they’re not as simple a garment as that name sounds. There are a quite a few details that can influence how comfortable a T-shirt is to wear. One of the most important of these is a T-shirt’s weight.

Most people still don’t think of T-shirts in terms of weight though. That’s because most T-shirt brands don’t really promote the dimension. A T-shirt is just a T-shirt and it’s as simple as that. No need to say any more. But we think that’s a mistake because the weight of the tee puts the T-shirt into perspective. Understand the weight and you get a better idea of when the tee should be worn. Put plainly, the weight is something you need to look out for if you want to feel comfortable in your tee across the seasons. And in this post we’re going to give you a bit more detail on what’s involved…

Here’s a quick summary of lightweight vs. heavyweight T-shirts but skip to the full article to get more detail:

Lightweight vs. heavyweight T-shirts – summary:

  • GSM (grams per square metre) is a measure that describes the weight of the tee
  • For lightweight / summer tees look for a GSM of 160 or under
  • For heavyweight / winter tees look for a GSM of over 200
  • For versatile / all-season tees look for a GSM of between 160 and 200
  • As well as the GSM, also consider the fabric (and avoid synthetics)
  • Regardless of the type of tee, a high-quality and sustainable T-shirt is ideal.

T Shirt ‘GSM’ – an important acronym:

Let’s get an important acronym out of the way first: GSM. It stands for ‘grams per square metre’ and is a measure of how much a square metre of a fabric weighs. It’s used in clothing to describe fabric weight.

A T-shirt with a higher GSM will be thicker and weightier. And the lower the GSM, the lighter the T-shirt would be. Simple.

Finding the GSM isn’t always so easy though as not all brands will add an indication of GSM. A quality T-shirt brand should have this detail included on the label, though, and if you see it it’s a good sign that thought has been put into the garment. We’ve added an indication of the GSMs you should be looking for under each type of tee that we’re going to look at, next.

The Lightweight T-Shirt

Lightweight T-shirts

  • GSM: under 160
  • Best in: summer and hot weather
  • Fabrics: cotton and innovative new durable lightweight fabrics, like Lyocell

What you don’t want in summer is a thick T-shirt that looks the part but suffocates the upper body. The low-GSM fabric of this kind of tee will keep you cool in the more intense heat and stops you from getting too sweaty.

Beyond the GSM you should also look for a T-shirt made from a fabric that’s light and breathable. Cotton is a great choice but there are some even more ideal (and sustainable) alternatives like Lyocell. Lyocell is a fabric derived from wood that is extremely light and breathable, and also less transparent than cotton in lighter weaves. It’s perfect for summer tees.

SANVT’s lightweight summer T-shirt is made from an optimal mix of premium cotton and Lyocell.

The Heavyweight T-Shirt

Heavyweight T-shirts

  • GSM: over 200
  • Best in: autumn, winter, and cold weather / conditions
  • Fabrics: premium heavyweight cotton, wool and hemp can also work

While the summer is the traditional season of the tee, that’s not to say that T-shirts can’t be worn across the seasons. But if you’re going to try and sport a tee in colder conditions then you’ll need one that’s designed for the purpose.

Heavyweight tees are just that and made from thicker fabric of a higher GSM. They keep you a bit snugger when the temperatures dip and are also more durable overall.

A factor to bear in mind with heavyweight tees is that while you want to feel snug you don’t want to compromise on breathability. Choose a T-shirt like our Heavyweight T-Shirt that’s made from a breathable, natural fabric and avoid uncomfortable synthetic blends that can irritate the skin and make you sweat more.

The perfect T-Shirt in three basic colours

All-season T-shirts…

  • GSM: between 160 and 200
  • Best in: most seasons but maybe in hotter climates opt for the lightweight tee
  • Fabrics: premium cotton is the classic, but a midweight can suit a wide range of fabrics

All-season T-shirts are versatile. They might lack the advantages of lightweight and heavyweight T-shirts in more extreme conditions but they work well in most conditions. It’s a useful type of tee to own and with a shirt like our Perfect T-Shirt you can't go wrong.

Like with the more specialist tees, the GSM is important and you should be aiming for a Tee within a range of around 160 and 200. Cotton is the classic fabric for this type of tee but opt for a high-quality and sustainable type of cotton, like GOTS-certified organic cotton. As a rule, avoid cheap cotton at all costs – whatever kind of T-shirt you’re buying.

Despite the versatility of this type of tee, if you are going to wear a tee in particularly cold or hot conditions then we’d recommend also having a specialist T-shirt to call on too.


Looking for your perfect T-shirt? Take the weight into account, that’s what we say. Check for the GSM and buy something that suits the season. It’s the way to look great and feel comfortable.

We also recommend choosing a T-shirt that’s high-quality and sustainable. That way, you’ll have the T-shirt for many seasons – whatever the conditions.

The following infographic will help you to keep this information in mind. You can download it here and share it with your friends.

You found the perfect T-Shirt for you? Find out more on how to care for a cotton T-Shirt so it lasts longer!