Why We Started With the Band: The Math Behind the BRABAR Movement
In 2019, BRABAR launched the "Shop by Band" initiative to address a problem the industry had ignored for decades: 8 out of 10 women are wearing the wrong bra size, usually a band that's too loose and a cup that's too small. The cause wasn't the women. It was the math.
BRABAR was founded by Wendy Herman, inspired by her own struggle to find a properly fitting bra for her 15-year-old daughter. That personal frustration became a broader mission: standardize bra sizing in the U.S., promote transparency about flawed measuring methods, and give women and teens the tools to find their real size instead of guessing.
The Rib Cage Method: Bust Minus Band Equals Cup
The rib cage method is straightforward: measure the underbust (the band size) directly, then subtract that number from the fullest part of the bust to get the cup size. Round the underbust measurement to the nearest whole number - if it's even, that's your band size; if it's odd, round up to the next even number. No extra inches added on top.
The Plus-4 Method: An Outdated Shortcut
The plus-4 method adds four inches to the underbust measurement to determine band size. It dates back to an era of less flexible bra fabrics, when a looser band was thought to be more comfortable. With today's stretch materials, it mostly just produces a band that's too loose to actually support anything - while inflating the number attached to the shopper's self-image in the process.
The Math, Side by Side
Four real examples show exactly how far apart these two methods land:
28-inch underbust, 34-inch overbust: Rib cage method: 34 - 28 = 6 inches → 28DDD/F. Plus-4 method: band becomes 32, so 34 - 32 = 2 inches → 32B.
32-inch underbust, 36-inch overbust: Rib cage method: 36 - 32 = 4 inches → 32D. Plus-4 method: band becomes 36, so 36 - 36 = 0 inches → 36AA.
36-inch underbust, 44-inch overbust: Rib cage method: 44 - 36 = 8 inches → 36G. Plus-4 method: band becomes 40, so 44 - 40 = 4 inches → 40D.
30-inch underbust, 37-inch overbust: Rib cage method: 37 - 30 = 7 inches → 30G. Plus-4 method: band becomes 34, so 37 - 34 = 3 inches → 34C.
Same body, every time - completely different size depending on which method is used. The rib cage method keeps the band snug where support actually comes from. The plus-4 method consistently produces a looser band and a smaller cup, which is exactly the combination that causes bands to ride up, straps to dig in, and cups to spill.
Three Methods, One Confused Customer
Part of what makes this so confusing is that the US market isn't even working from one wrong method - it's working from at least three different ones, often at the same time. In addition to the plus-4 method and the rib cage method above, there's also the armpit method: measuring higher on the torso, near where the straps meet the cup, rather than at the rib cage - the method Victoria's Secret's own instructions describe. Because the torso is wider up near the bust than it is underneath it, this produces a larger band number by design. All three methods still use the same underbust-to-overbust math to figure out the cup once a band number is set - but three different starting points for that band number means three different final sizes for the exact same body.
Why We Started With the Band
80% of a bra's support comes from the band, not the straps. For decades, the industry treated cup size as the headline measurement and band size as an afterthought. BRABAR flipped that: the band is the foundation, so it's where fitting has to start. A bra should feel snug like a hug around the ribcage - not like it's hanging from the shoulders.
Real, Measurable Industry Movement
Since 2019, we've tracked how the conversation around bra fit has shifted - using tools like the Wayback Machine to compare how brands discussed sizing before and after the BRABAR Movement gained traction. More brands are now referencing the rib cage method and being more transparent about their sizing. Progress is real, but incomplete: some brands have adopted the rib cage method in name while still adding two or three inches on top of it, a half-measure that still misses the point.
That's why this remains a movement and not a finished project. BRABAR carries band sizes 28 through 38 and cups A through DDD/F specifically because the smaller-band, fuller-cup combination is exactly what the plus-4 method fails hardest - and exactly where we're focused on proving a better standard works.
How to Measure for Yourself
Band size: Wrap a soft measuring tape around your ribcage, directly under your bust, keeping it snug but not tight. Round to the nearest whole number - if even, that's your band; if odd, round up to the next even number.
Bust size: Wrap the tape around the fullest part of your bust, keeping it parallel to the floor.
Cup size: Subtract your band size from your bust measurement. Each inch of difference is one cup size up from A.
Use BRABAR's Fit Guide and Bra Size Calculator to walk through this with your own measurements.
Shop by Age & Find Your Fit
BRABAR designs for every stage of development, not a one-size-fits-all age bracket:
A Better Fit, Built From the Ground Up
This started as one mother trying to solve a real problem for her daughter. It's become a standard we hold every product to, and a case we keep making to the rest of the industry: the band is the foundation, the math should be honest, and every body - especially the smaller-band, fuller-cup bodies the industry has underserved the longest - deserves a bra sized to fit, not a formula that fits the industry's convenience.
