As an experienced swimwear manufacturer, we have seen many startup brands encounter problems during production. One of the most easily overlooked—and potentially most damaging—mistakes can be hidden in something as simple as a size chart.
Just last month, we saved a 500-piece production order at the last possible moment. The cause of the crisis was surprisingly simple: to save time, the client had copied another brand’s size chart.
Today, I want to share what happened. If you are preparing to launch your own swimwear collection, I hope this story helps you avoid a mistake that could put your entire production run at risk.
The Hidden Risk Behind a “Perfect” Size Chart
Our client was a talented independent designer with an impressive collection. While we were confirming the order details, she sent us a size chart.
“I created this by referring to several established swimwear brands. Please use it to develop the patterns,” she wrote in her email.
At first glance, the chart looked completely standard. The progression of the bust, waist, and hip measurements from one size to the next also appeared reasonable. The production schedule was tight and the fabric had already arrived, so the obvious next step would have been to begin pattern development and production planning immediately.
The Critical Problem We Found Before Cutting
While grading the production patterns according to the client’s size chart, our pattern maker noticed that something was not right.
Swimwear is made from highly elastic fabric and fits much closer to the body than ordinary clothing, making it far more sensitive to measurement errors. When our pattern maker checked the hip increments between the medium and large sizes, we discovered that the entire production run would be significantly too small through the hips if we followed the client’s chart exactly.
Why had this happened?
After an urgent review, we identified the cause. The reference brand whose size chart the client had copied used a very close, performance-oriented fit with fabric that had relatively limited stretch. Our client, however, had selected a heavier shaping fabric with strong compression.
More importantly, the client’s design featured a deep V-shaped opening at the back waist. If the hip measurement was too small, the fabric tension would be concentrated around the waist. The finished swimsuit would dig into the wearer’s body and, for some customers, could be impossible to pull over the hips.
If we had not stopped to check and had sent the patterns directly to the cutting room, all 500 swimsuits could have become unwearable products. For a startup brand, this would have meant more than a financial loss. It could also have caused serious damage to the brand’s reputation.
The Solution: Revising the Patterns Before Production
As soon as we confirmed the problem, we immediately stopped the cutting process and contacted the client.
During a video call, we demonstrated the fabric stretch test and showed her how the original size chart translated into the actual patterns. Once she saw the comparison, she realized how serious the risk was.
“Oh my God. I thought size charts were universal,” she admitted.
Our pattern-making team then worked quickly to recalculate the hip and leg-opening grade rules based on the stretch factor of the selected fabric and the construction of the design. After two rounds of sample fitting, we finalized the correct measurements and successfully completed the 500-piece production run.
Our Advice to Swimwear Brands: Never Copy Another Brand’s Size Chart
This experience reinforced a principle we repeatedly emphasize in swimwear manufacturing. If you are developing your own swimwear products, keep the following three points in mind.
1. Size charts are never universal
Even within the same brand, different styles—such as one-piece swimsuits and bikinis—require different sizing considerations. Copying another brand’s size chart means forcing your customers to fit someone else’s design logic.
2. Fabric stretch can determine whether the sizing succeeds or fails
This is one of the most commonly overlooked factors. Nylon and polyester fabrics behave differently, and heavier fabrics and lightweight fabrics can also have very different stretch rates. Your size chart must be closely connected to the characteristics of the final fabric.
Before developing a pattern, we test every fabric in both the horizontal and vertical directions. We then use those results to determine the appropriate measurements.
3. Let your manufacturer participate in developing the size chart
A professional swimwear manufacturer should be more than a company that simply follows production instructions. It should also be your technical partner.
When sending your designs to the factory, explain the body characteristics of your target customers and the fit you want to achieve. For example, do they prefer high-waisted styles with more coverage, or higher-cut silhouettes with a more revealing fit? Your manufacturer’s pattern maker can then develop a size chart suited to your fabric, design, and target customer.
Final Thoughts
Swimwear allows very little room for error. Even a difference of one centimeter can become much more noticeable when a close-fitting garment is stretched over the body.
Do not let a size chart copied for convenience ruin a product you have worked so hard to design.
Finding a manufacturer willing to examine the patterns one more time and verify the fabric stretch before cutting may be one of the most valuable investments you can make in your swimwear brand.
