Tired of Returning Bras? Here’s What We Discovered from Real Shopping Data!

If you’ve ever bought a bra online and returned it because it didn’t fit quite right, you’re not alone. The struggle of finding the perfect bra size is real, and many shoppers rely on their “usual size” rather than exploring a size that may actually fit them better.

But what if trusting a bra size calculator could drastically reduce your chances of returning a bra?

From October 2024 to February 2025, we conducted an A/B testing study to analyze how product recommendations impact return rates. The results were eye-opening:

• When users picked bras from a general listing, 20% of them ended up returning their purchase.
• When users followed a direct product recommendation, only 5% returned their bras.

Let’s dive into the details.

The Experiment: How We Analyzed Bra Returns

To conduct this study, we leveraged Amazon Associates affiliate data, which tracks product purchases made through our referral links. This data provided key insights into shopping behaviors, allowing us to compare how different types of product links influenced purchase decisions and return rates. Here’s how we gathered and analyzed the data:

1. Tracking Purchases Through Amazon Associates

As an Amazon affiliate, we embed special tracking links in our content. When users click on these links and make a purchase, Amazon records:

• Which link the user clicked (a specific product vs. a general category page).
• What they ultimately purchased (it could be the recommended item or something else).
• If the product was returned within Amazon’s return window.

This allowed us to separate users into two groups:

• Users who purchased through a direct product link (a specific bra recommended based on size).
• Users who browsed a general bra category page and made their own selection.

2. Analyzing Purchase and Return Trends

Over a five-month period (October 2024 – February 2025), we collected data on:

• Total number of bras purchased.
• How many were returned.
• Which type of link led to the purchase.

To ensure accuracy, we hired a data analytics expert skilled in SQL and Python to clean and refine five months of purchase data (October 2024 – February 2025). Removing irrelevant items allowed us to focus solely on bra purchases, ensuring clear and reliable insights into buying and return patterns.

Furthermore, we filtered out non-bra returns to avoid skewing our return rate calculations.

This meant isolating returns only for bras, ensuring that our final dataset accurately represented the impact of product recommendations on return rates.

The Findings: Return Rates Tell the Truth

Return Rate for Generic Link Users

• 20% of purchases were returned.
• These users were not directly recommended a bra based on size but instead picked one on their own.
• Many likely chose a size they had always worn, unaware that their true size might be different.
• Additionally, when users clicked on an affiliate category link (which led them to a general listing of bras), they were also susceptible to purchasing other non-bra items. This added noise to our data, making it necessary to carefully filter out irrelevant purchases.

Return Rate for Direct Product Link Users

• Only 5% of purchases were returned.
• These users trusted the bra size calculator’s recommendation and were directed to a specific bra product page rather than a general category page.
• To maintain accuracy, we counted the unique SKU (Stock Keeping Unit) number for each bra purchased, tracking how many of those specific SKUs were sold and how many were returned.
• The drastic difference in return rates—5% for direct recommendations vs. 20% for self-selected purchases—proves that precise recommendations lead to better fit and fewer returns.

Key Comparison:

• 20 out of 100 users returned their bras when they browsed and selected their own size.
• Only 5 out of 100 returned their bras when they followed the recommended size.

What Else Did We Find from the Data?

In addition to identifying the most popular bra brand (HSIA Lingerie) and the most common size (34DD), we uncovered several other interesting insights from our data analysis.

One of the most interesting findings was that many customers purchased two bras—either different sizes or styles—just to be sure, and then returned one.

This explains why some of the most popular brands, like HSIA Lingerie, DELIMIRA, and Playtex, also had higher return rates.

Since these brands were purchased more frequently, the volume of returns naturally increased.

We also saw that premium brands like b.tempt’d by Wacoal and Calvin Klein had some of the highest return rates.

On the other hand, budget-friendly brands like Fruit of the Loom and Bali had the lowest return rates, likely due to their consistent sizing and comfort, reducing the need for returns.

Brands that focused on comfort, such as Vanity Fair and Glamorise, had moderate return rates, indicating that customers were generally satisfied with their fit.

Rather than being a sign of dissatisfaction, the return data reflects smart shopping behavior.

The high return rates for popular brands show strong customer engagement and trust in these products, as shoppers felt comfortable experimenting to find their perfect fit.

Why Do So Many People Choose the Wrong Bra Size?

The data from our study aligns with a long-standing issue: bra sizing misconceptions.

1. Many shoppers stick to the size they “think” is right.
2. They overlook sister sizes, which might actually fit better.
3. They assume all brands fit the same, even though sizing varies widely.

Most people have a bias toward their go-to size, even if it’s not the best fit for them. The bra size calculator eliminates this guesswork by suggesting a size that aligns with their actual measurements, not just their assumptions.

Why You Should Trust the Recommendation

1. It’s data-backed, not just a guess.
2. It considers sister sizes that might fit better.
3. It drastically lowers return rates, meaning a higher chance of getting the perfect fit the first time.

Moral of the Story: Trust the Size Calculator!

The numbers don’t lie—following a bra size recommendation reduces your chance of buying the wrong size. Your usual size might feel familiar, but a calculated size might actually be the right one for you.

So, next time you shop for a bra online, let go of your sizing bias and trust the recommendation. Your perfect fit is just one click away!