a woman wearing a 1960s vintage peach pink boucle woven skirt suit set

How To Make Sense of Sizing

Finding the perfect size when thrifting online is often a challenge. Therefore we created a new feature, Convert Size.

  • Liisa Jokinen

  • Jan 16, 2024

Clothing sizes are a jungle of odd letters and numbers and their weird combinations. They are supposed to help us find the right fit but oftentimes they just confuse the consumer. They can even be conflicting.

Sizes are tricky because there are so many size systems in use, and many of them have changed throughout their history. A blouse that was size L in the 70s, would nowadays be more like M or even S. A 50s dress labeled as a size 12 might be a modern size 6 – or even smaller. Vintage sellers refer to these original sizes as “vintage sizing”.

Marilyn Monroe in 1953
Marilyn is known to have worn US size 14 Pucci blouse in 1962, but according to her measurements, her modern size would be approximately US 6. • Photo: Los Angeles Times UCLA
Marilyn is known to have worn US size 14 Pucci blouse in 1962, but according to her measurements, her modern size would be approximately US 6. • Photo: Los Angeles Times UCLA

The reason why the sizes have changed over the decades, is the so-called vanity sizing: as we people have grown taller and larger, brands have started to make their clothes bigger while keeping the size label the same. Sizing has become a marketing tool instead of being a useful number determining your clothes size. This is understandable: We shoppers prefer to buy clothing labeled with small sizes because it boosts our confidence.

“As Americans have grown physically larger, brands have shifted their metrics to make shoppers feel skinnier – so much so that a woman’s size 12 in 1958 is now a size 6. Those numbers are even more confusing given that a pair of size 6 jeans can vary in the waistband by as much as 6 in., according to one estimate. They’re also discriminatory: 67% of American women wear a size 14 or above, and most stores don’t carry those numbers, however arbitrary they may be”, writes Eliana Dockterman in Time article.

Lack of standards

Unfortunately, there are no standards for clothing sizes which further complicates the issue. A clothing brand can decide what they consider as size 6 or M – or even create their own sizing. That’s why we often ask: How does “a Marni size run”? “Marni tends to run small, loose, big, etc”. Different brands owned by the same corporation can have inconsistent sizes as the brands cater to different target groups.

Many European countries have their own sizes – even a US customer runs often into UK, IT, and FR sizes. But did you know that the German size DE is used in all Scandinavian countries, too?

The most standardized sizes are women’s and men’s shoe sizes. There are multiple reasons for this: feet are simpler to measure – oftentimes just the length of the foot is enough information whereas even making a simple garment must take into account multiple measurements and body dimensions. Secondly, shoe manufacturing became industrialized before clothing manufacturing which led to earlier adoption and spreading of the standard sizes.

Clothing sizes as we know them now arrived when made-to-measure clothes were replaced by factory-made, mass-produced ready-to-wear clothing. This was accelerated by the Civil War and other wars of the 19th century which required unprecedented numbers of uniforms. A size system was needed to quickly produce large amounts of uniforms – there was no time to measure every single soldier.

Before this, most clothing was tailor-made to fit individual measurements. Gradually ready-to-wear clothes became more common. But the problem remains: our bodies are not standardized so there is not a size system that would work for all bodies.

a clothing tag of a Vintage Talbots Pink Button Suit Jacket Women Size 4 Petite
Photo: TheVintageHive on Mercari
a clothing tag of  a men’s Vintage Towncraft Plus Penn Prest Penneys Barrel Cuff Tapered Shirt Size M
Photo: countrypicker20 on eBay
Photo: TheVintageHive on Mercari
Photo: countrypicker20 on eBay

Plus, Petite, Tall

In the mid-20th century, fashion brands and clothing manufacturers realized they could and should cater better to people with different body types. The pioneer in the field was the American company Lane Bryant who in the 1920s launched a line 'For the Stout Women' which ranged between a 38-56 inch bustline. But it was first in the 70s and 80s that plus sizes started to gain ground. First, plus-size clothes were just bigger versions of smaller-sized garments but gradually manufacturers have started to take into account height and body proportions rather than just waist and bust measurements when developing the plus sizes. Similarly, petite and tall sizes adjust not just the length of garments, but also proportions such as torso length and waist placement to better fit shorter or taller frames.

Nowadays, there is not only one but several plus sizes in use globally: US plus size (a number and letter W combination), international plus size (a number and a letter X combination), and plus letter size. Although US regular sizes are not the same as plus sizes, people often call regular sizes bigger than 18 plus sizes. So pay attention if a garment is just called “plus size” because of its looser fit or bigger number, or if its size tag is truly following a plus size chart.

Men have their plus-sizes, too. They usually start at around XXL, or a waist size over 40 inches. The first “big and tall” departments were born in the 60s and 70s and they catered to men who did not fit into regular sizes. The market grew bigger in the 80s and 90s when different body types became more accepted and awareness of size inclusivity grew.

Some brands also use unisex sizing which is designed to fit a wide range of body types regardless of gender. The clothes that follow unisex sizing tend to be more relaxed or straight in their fit and their sizing closer to men’s sizing than women’s as women’s bodies are usually curvier and smaller than men’s bodies. Typically a regular women’s size L matches unisex M, and men’s S. But it varies, so check out the measurements and brand’s fit and size guides if possible. There is also unisex plus sizing.

The only truth: the measurements

Because the size systems are not standardized and they vary across brands and decades, the only truth in sizing is the measurements when shopping online. If you want to know the true and real size of the garment, check out the measurements in the listing, and compare them to your own before buying. Ask the seller for more measurements if needed – most sellers are happy to help!

It is a good idea to save your measurements on your phone so you will always have them at hand, whether you are shopping online or in person.

How to take your measurements? There are multiple guides online on how to do it – just follow the instructions carefully. Re-measure yourself once a year as our bodies naturally change as we age.

If you are shopping for a contemporary garment and label, check if the brand has a sizing chart on its website so you can compare the clothing label to your sizes for the most accurate fit.

Lastly, keep in mind that body measurements are different from garment measurements. Sellers usually measure the garment from seam to seam – remember to add extra inches to your body measurements, if you want a looser fit.

Convert Size

To help you quickly make sense of sizing, we have built a new feature called Convert Size.

Gem Story image
Gem Story image
Gem Story image

You can find the Convert Size feature on the Gem main menu or use it on the product page. It covers over 40 international size systems, grouped into ‘families’:

Women’s regular
Women’s plus
Women’s petite
Women’s shoes
Men’s regular
Men’s plus
Men’s shoes
Unisex regular
Unisex plus

With the Convert Size you can search for any size or size system, and convert it to the selected size systems or measurements. On the product page, you can tap the the size labels, and view conversions to other systems.

Just a little disclaimer: As we mentioned earlier, the size systems are not standardized, and therefore the size conversions are approximations. Although Convert Size results are approximate they help you quickly scan if the item is close to your size or not. We always encourage you to check the garment measurements before purchasing, if possible.

Hot tip for sellers! You can easily copy and paste size conversions from the table if you are listing an item and want to include several sizes in your listing info.

Copy size conversions from the table

No matter how complicated the sizing is, this should not stop you from buying secondhand. Just know your measurements, compare them carefully to the listing, and remember that it is the fit that counts – not the number on the clothing tag.

One Size Fits None
A brief history of sizing systems
Marilyn Monroe’s True Size
Wikipedia: Vanity sizing

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