Bra Sister Sizes: The Ultimate Guide
ALL ABOUT
BRA SISTER SIZES
Discover how sister sizes simplify the search for a perfectly fitting bra.
This guide is designed to help you find your ideal fit.
QUICK SUMMARY
Bra sister sizes are alternative sizes that share the same cup volume.
Sister sizing helps you find a comfortable fit when your usual size isn’t quite right.
If the band size increases, the cup size decreases to maintain the same volume.
A properly fitting band is key since it provides most of the bust support.
Understanding sister sizes expands your bra-fitting options.
FINDING YOUR PERFECT FIT
HAS NEVER BEEN EASIER
Many believe they are limited to one bra size, which can lead to discomfort and poor support when that size doesn’t fit quite right. Bra sizing can vary significantly depending on the style, making it essential to find the right fit, which can sometimes feel overwhelming. But it doesn’t have to be. Sister sizes offer a range of alternative sizes when your usual go-to isn’t available or when the band feels too tight or loose. This method works by adjusting the measurements of the band size while adapting the cup volume, without altering your proportions entirely.
Every woman deserves a bra that provides both support and comfort. To help you achieve that perfect fit, we have created a comprehensive Sister Size Guide. It will help you understand the balance between band size and cup size, two crucial factors that play a vital role in providing proper support and enhancing your overall wearing experience. With the right fit, you can feel confident and comfortable all day long.
WHAT ARE BRA SISTER SIZES?
Bra sister sizes are all about finding a better fit by understanding how band and cup sizes work together. They are alternative bra sizes that have the same cup volume but different band sizes. When the band size changes, the cup size adjusts too, so the cup holds the same breast volume. This means if your usual bra size feels too tight or loose in the band, you can try a sister size to get a better fit without sacrificing support:
If the band feels too tight, size up the band while decreasing the cup size.
If the band feels too loose, size down the band while increasing the cup size.
For example, a 34C, 32D, and 36B all have the same cup volume but differ in band length. A bra’s cup size is not determined by volume alone; its fit also depends on the band size. The main difference between sister sizes lies in the band length and the shape of the cup, which adjusts to accommodate changes in your underbust measurement.
HOW DO BRA SISTER SIZES WORK?
Finding your sister size involves balancing the band and cup measurements to ensure that the overall cup volume remains consistent. When you increase your band size, you should decrease the cup size to achieve the exact fit. This adjustment is crucial because the cup's volume needs to complement the larger band. On the other hand, if you decide to go down a band size, you must correspondingly increase the cup size to maintain the correct fit. Let's break it down further for clarity.
For instance, if you wear a 34C (which corresponds to size 4 in the chart) but find the band too tight, you could try a 36B instead. Both sizes hold the same cup volume, but the 36B has a longer band and a slightly smaller cup to balance that. Conversely, if the band feels too loose, try a 32D, which has a shorter band and a slightly larger cup volume, keeping the overall fit consistent.
Let's use size 34B as another example.
TO GET A SMALLER BAND:
If the 34 band feels too loose but the B cup fits perfectly, you would go down one band size to 32. To maintain the same cup volume, you must go up one cup size to C. Therefore, your sister size is 32C.
TO GET A LARGER BAND:
If the 34 band feels too tight but the B cup fits perfectly, you would go up one band size to 36. To keep the same cup volume, you must go down one cup size to A. Then, your sister size is 36A.
BRA SISTER SIZE CHART
Find your sister sizes by consulting the chart to identify your current bra size. Once you’ve located your size, look along the diagonal row that includes your size. Each size in this diagonal corresponds to the same cup volume but varies in band size. This allows you to explore other sizes that might offer a better fit or more comfort, while still providing the same level of support.
| CUP SIZE | ||||||
|---|---|---|---|---|---|---|
| BAND SIZE |
A | B | C | D | DD | E (DDD) |
| 32" | 1 | 2 | 3 | 4 | 5 | 6 |
| 34" | 2 | 3 | 4 | 5 | 6 | 7 |
| 36" | 3 | 4 | 5 | 6 | 7 | 8 |
| 38" | 4 | 5 | 6 | 7 | 8 | 9 |
| 40" | 5 | 6 | 7 | 8 | 9 | 10 |
| 42" | 6 | 7 | 8 | 9 | 10 | 11 |
FAQ
Yes, sister sizing is an effective way to find alternatives for your bra size while keeping the same cup volume. When you change the band size, the cup size also shifts to maintain balance, so a larger band corresponds to a smaller cup size, and a smaller band corresponds to a larger cup size. It’s essential to keep in mind that even though the cup volume remains the same, the overall shape and fit of the bra can feel different. A smaller band size will bring the straps closer together and adjust the position of the underwires, whereas a larger band size will have the opposite effect. This approach helps you change the band fit without compromising support.
A sister size bra is a great option when your usual size doesn’t quite fit right, especially if the band feels uncomfortable but the cup volume is correct. If the band is too tight or too loose, switching to a sister size can help you achieve a better fit while maintaining the same level of support. This adjustment involves changing the band size up or down and compensating by adjusting the cup size in the opposite direction to ensure you keep the same cup volume.
It’s also helpful to know when trying different brands or styles, as sizing can vary significantly. A size that fits well in one brand may not feel the same in another, so being aware of your sister sizes gives you more flexibility. This knowledge is practical during sales or when your preferred size is unavailable, allowing you to explore alternatives without compromising comfort or support.
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