Apparel sizing is a broken system. Take a moment to grab a few items from your closet. Do your clothes all have the same size label? Unless you shop exclusively from one brand, your wardrobe most likely spans a few sizes; you might wear a medium for one brand, but a large for another. And no, it’s not because your body has changed as much as you think it has. The truth is that the numbers on those labels are arbitrary, and there isn’t really a standardized apparel size system these days.

In this post, we want to discuss why the apparel sizing system is not only a common shopper frustration, but also a potentially big problem for your e-commerce store. To understand why, it’s worth understanding a little about how the modern sizing system came to be.

Size charts are a relatively new concept; they weren’t necessary back when people made their own clothes or had them tailor made. Size charts became necessary when ready-to-wear clothes became popular, and so in 1939 the U.S. commissioned a study to measure the bodies of 15,000 women in order to create a standard system. This system, which was created in 1958, failed for several reasons- the numbers were arbitrary (so women wouldn’t have to share their true measurements with others), and it wasn’t inclusive of all body shapes[1].

Fun fact: a size 8 dress today was a size 16 dress in 1958.[2] Vanity sizing is also to blame for the lack of standardization- as people grow bigger, brands are sizing down to make shoppers feel more confident about their bodies and purchases. However, these brands aren’t adhering to a standard and are rather basing their sizes on their respective target consumer audience. An article by TIME shows just how differently a “size 8” can be defined today – for Zara, it means 27.6” in the waist, but for Calvin Klein it means 29.5”[3].

Thanks to all these factors, rather than having standards in clothing sizes, what we’re left with today are rough “references” at best. Different countries also have different systems, and, to top off the absurdity, even shirts within the same brand may size differently depending on the design and fit. It’s not difficult to see why this lack of standardization is a nightmare for shoppers, especially when it’s become more popular to browse and purchase online, where it’s impossible to replicate the same offline experience of trying on a product.

Why sizing is a problem for online shopping, and how to prevent losses from your e-commerce store
Photo by Tim Gouw / Unsplash

Unfortunately, this isn’t just a problem for shoppers. Sizing problems plague e-commerce merchants in several ways:

1 – According to Digital Commerce 360, poor fit/ incorrect sizing is the most common reason for returning an online order[4]. In fact, TIME estimates that 40% of online purchases are returned, mostly due to sizing issues. Because of unreliable sizing systems, practices like bracketing – purchasing multiple sizes of the same item online and returning the ones that don’t fit – are trending and contributing to huge losses for online retailers.

Returns not only lead to lower profits due to the lost sales, but also higher costs due to the extra labor necessary for inspecting and restocking the returned goods. Sourcing more merchandise to keep inventories stocked also comes with extra costs. It’s important to keep in mind as well that an estimated half of all products no longer have value once returned, and therefore probably can’t be resold[5].

2 – Uncertainty over sizing can lead to purchase hesitation and lower conversion, especially for those who don’t have the means or time to buy now, return later. Without a reference product from the same store, a first-time shopper takes an even higher risk when making their first purchase from a new store. Unless they find a way to instill higher buying confidence in customers, new e-commerce merchants struggle to increase conversion and profit.

3 – Unclear sizing on products leads to a drain on overhead, as merchants need to allot more manpower to handling individual inquiries from shoppers regarding sizing.

Why sizing is a problem for online shopping, and how to prevent losses from your e-commerce store
Photo by Ali Yahya / Unsplash

As a new e-commerce merchant, you’ll understandably be focused on your storefront, products, and sales, but it’s important to also keep an eye out on overheard costs and lost potential sales.

Thanks to modern technology, there are now a growing number of solutions out there to tackle the sizing problem. An easy one that may be worth investing in is Kiwi Sizing. With plans starting at $0 per month (yes, that means free!), Kiwi Sizing is a beginner friendly software that helps merchants easily build custom size charts.

It also comes with a handy size recommender tool. You can easily add it as a widget to your product pages, thanks to its seamless integration with e-commerce platforms such as Shopify, WooCommerce, and BigCommerce. As an added bonus, Kiwi Sizing also has a function that converts between international sizes so that your global customers have a better shopping experience.

Not only will Kiwi Sizing help save your customers time from figuring out the correct size to purchase, it will free them from the hassle of returns, which will make them more likely to come back and shop again. In turn, you’ll see an increase in conversion and a decrease in costs and losses. It’s a win-win!

Click here to check out a Kiwi Sizing demo, and learn more about how you can reduce returns and increase conversion for a more successful e-commerce store.


Kiwi Sizing is an e-commerce plugin to help solve the sizing problems for online shopping. Over 40% of online clothing returns are due to sizes. Kiwi Sizing is designed to make sizing easy by offering stylish size charts and easy-to-use fit recommenders that let shoppers know what is the best size to purchase. We help improve conversions, cut down on returns, and lower the needs for customer support.

We are trusted by thousands of Shopify stores with over 400 5-star reviews. Try it now for free and start reducing unnecessary returns.