You Deserve a Bra That Actually Fits
Shocking, I Know
Is the “plus-four” sizing method outdated or inaccurate today?
FIT GUIDE
brabar
FIT GUIDE
BRABAR
FIT GUIDE
You deserve better than what the bra industry is ready to give you, but we are trying t make comfort and support more accessible.
By: Lucy DiChristina
So short answer, yes, the plus four method is extremely outdated, inaccurate and honestly unsuccessful today. Wait…why are people telling me to add four inches to my bra size? Have you ever wondered why some brands recommend going in person to get an accurate bra size? It is because industry standards have become unnecessarily complicated and made bra sizing frustrating.
What Is The History Of The Plus Four Method?
Well, not to get overwhelmingly technical, but the first bra was patented in 1914. Back then, women were constantly being confined and limited, and their bras were no different. Since women's bras were made of such constrictive materials, it was necessary to add 4 to your measurements to account for the fact that the fabrics had no give to accommodate different bodies. As you can imagine, as over one hundred years have passed, bra styles have been completely flipped upside down and evolved. Bras now can be made out of almost every fabric and we no longer have to worry about the material of our bras not being able to handle a deep breath. So why has our sizing method not evolved along with the evolution of the actual product? The truth is that the industry is just a little stuck in their ways and has convinced themselves that they have found the right way to find people's bra size even if it is no longer a successful method of actually fitting women into bras that make them look forward to getting dressed in the morning. Back in 1914, bras were anything but accessible, so mass production began streamlining the bra process, which forced the plus four methods into existence. At the time, this method opened doors for women, so they sacrificed their comfort in order to have access to a necessary garment. This reality did not allow women to have any access to professional fitting so there needed to be an easy at-home method for women to find new and revolutionary answers to problems that had plagued them for generations. So naturally, the goal in this time was to make bras that could be as widely used as possible but not necessarily at all focused on the precision of fit. Solving this problem has created a whole new problem for the modern age, and it is time we address it.
How Is The Plus Four Method Used?
On the surface, the plus-four method seems simple enough. You start by measuring your ribcage (underbust), which is the area directly beneath your breasts where your bra band sits. Then, instead of using that measurement as your band size, you add four inches (and sometimes even five) to it. For example, if your underbust measurement is 28 inches, the plus-four method would place you in a 32 band. So basically according to this a 28’’ ribcage measurement equals a 32 band. From there, your bust measurement is used to calculate your cup size based on the difference between the two numbers. Many sizing calculators and fitting guides still rely on some version of the plus four method today, which is why so many women are walking around in a bra size that actually makes no sense when you reference their actual measurements. But there's an important detail hidden in this formula: the very first step moves sizing away from your actual body measurements. If your ribcage measures 28 inches, your body hasn't suddenly become 32 inches around just because a sizing formula says so. Yet that's exactly where the plus-four method begins. Before you've even tried on a bra, the sizing system has already added inches that don't exist on your body, obviously setting women up to fail and be confused about why their bra does not fit right, even when they got it professionally fitted.
"the plus four method is holding bras and women back from reaching their full potential. "
How Have Bras Developed?
Now, in 2026, it is as if every aspect of the bra industry has evolved except for the measurement strategies. This commitment to using historical practices is as if we were still using paper maps to figure out where to go, even though GPS exists and is more accurate. I know there are a lot of issues with the bra industry but it is extremely impressive the way the bra has become modernized. You can find a bra in almost every material that is meticulously designed and manufactured. Bras have so many different styles (even if we don't understand what each style is for) specifically designed to make your outfits perfect. But, the plus four method is holding bras and women back from reaching their full potential.
How Can The Plus Four Method Interfere With A Well Fitting Bra?
I know I have explained why four inches have been historically added to bra sizing but now let me explain how it gets in the way of finding a well fitting bra. Eighty percent of bra support comes from your band, so when you are wearing the wrong band size that is off by four or five inches your band size is being sabotaged from the first step of the bra fitting process. plus-four, inevitably, is about why the ribcage should be the foundation of bra sizing anatomically. When your band size is too large, not only is your bra not capable of giving full support but other parts of your bra begin to compensate for the failure of the band. When your bra band is too big your bra straps will dig into your shoulders because it will be your straps that are then held responsible for supporting your breasts. The only way that bra straps can attempt to support you is by hanging them as tightly as possible which of course results in the straps digging into your shoulders. Also, when your band is too big it will ride up your back which is extremely uncomfortable, in lieu of searching for a tighter band most women will then strap their bras to the tightest setting (which should never feel necessary in the right bra). It is this compensation which makes so many women's bras fit incorrectly and make women think that there is no such thing as a well fitting bra that is comfortable while being supportive.
What Is The Armpit Method?
Many traditional fitting systems used what is often called the "overbust" or "high-bust" measurement. This measurement is taken around the upper chest, above the breasts and close to the underarm area. But why are we measuring our armpits if our band sits on our ribcage? The answer is, it really does not make any logical sense. Retailers would then combine this number with other measurements and formulas to estimate a bra size. The problem is that this measurement doesn't directly correspond to the part of the body responsible for supporting the bra. Your bra band sits around your ribcage, not your armpits. When sizing methods rely heavily on measurements taken above the bust, they introduce unnecessary variables. Shoulder width, muscle distribution, posture, and breast shape can all influence upper-chest measurements. Two people with identical ribcage measurements may have very different high-bust measurements, leading to inconsistent sizing recommendations.
What Is The Band Size Solution?
Don’t worry there is a solution, shopping by your band size! The straps and cups certainly play important roles, but without a properly fitting band, the entire bra struggles to function as intended. Think of the band as the foundation of a house. You can have beautiful walls, windows, and a roof, but if the foundation is unstable, everything built on top of it becomes less effective. The same principle applies
"without a properly fitting band, the entire bra struggles to function as intended. "
to bras. If the band is too loose, the cups cannot sit correctly, the straps begin compensating for lost support, and the overall fit becomes less comfortable. Instead of beginning with a cup letter, start with your underbust measurement. Your ribcage measurement provides the foundation for determining which band sizes are most likely to work for your body. Once the band is established, cup sizing becomes much easier to evaluate.
One Last Thing Before You Go
At BRABAR, we encourage girls to think about bra sizing from the ground up. Start with the band. Start with the ribcage. Start with the measurement that reflects the part of your body responsible for support. When you know your underbust measurement, shopping becomes simpler. You can evaluate bras based on how they are designed to fit your frame rather than relying on outdated formulas or confusing sizing charts.
XOXO BRABAR
STILL HAVE QUESTIONS?
FAQS
The plus-four method originated when bras were made from less flexible materials and mass production prioritized accessibility over precision. Adding four inches to a person's ribcage measurement helped accommodate the limitations of early bra construction. While that approach may have made sense over a century ago, modern bra fabrics and manufacturing techniques have evolved dramatically, prompting many to question whether the method is still necessary today.
Because the plus-four method adds inches to your actual ribcage measurement, it can place you in a band size that is larger than your body requires. Since the band provides most of a bra's support, a loose band can cause other fit issues, such as straps digging into your shoulders, bands riding up in the back, and a lack of overall support.
Start with your underbust (ribcage) measurement. Your band size is based on the part of your body that actually supports the bra, making it the foundation of a good fit. Once you've established an accurate band size, it becomes much easier to determine the cup size that works best for your body and evaluate whether a bra truly fits.
