What is a Sister Size?

Finding a well-fitting bra can sometimes seem like a tough task, the struggle is real - whether you're trying a new style, experimenting with something risky or just getting yourself some new bras. While knowing your correct size is essential for the perfect fit, understanding your breasts and what makes you feel comfortable is important too.
Understanding Sister Sizes is something every girl should know, because you never know when it comes handy, like - a pretty design ran out of your cup size, your current bra just doesn't sit right, or a slight variation in your cup size isn't getting you the perfect fit.
What is a Sister Size Bra?
A sister size bra refers to a bra that has the same cup volume as another bra, but with a different band size. This means that if you find your perfect bra size, but the band feels too tight or too loose, you can try a sister size to get a better fit. For example, if your regular bra size is 34C, you can try a sister size of 36B or 32D, as they both have the same cup volume but different band sizes.
You have a basic understanding of bra sizes by now, they are basically ratios - band: bust. The easiest way to understand is - as cup size goes up, the band’s width must come down to maintain the ratio of the cup size. As the band size increases around the rib cage, the cup size should decrease.
How do you Calculate your Bra Sister Size?
Now, here’s the fun part. Sister sizing takes a 32C and makes it equivalent to a 34B and a 30D too! This gives you so much more scope to explore the world of lingerie styles, sizes and more.
Sister Sizes usually run in opposite directions with one-size shifts. Confused? Don’t worry, we’re here to help.
Sizing Down: One size smaller than your current band size and one letter (A, B, C, D) larger than your current cup size. Eg: If you wear a 36C, your sister size down will be 34D.
Sizing Up: One size larger than your current band size and one letter (A, B, C, D) smaller than your current cup size. Eg: If you wear a 32C, your sister size up will be 34B.
Wondering Whether to Size Up or Down? We’ll Tell You.
Which hook do you wear your bra on?
● If your answer is “the tightest hook,” sizing down might work.
● If your answer is “the loosest hook,” then you could try sizing up!
● If your answer is “the hook in the middle” then you could try either going up or down!
You’ve got all the information you need. Now find your sister sizes in the amanté Bra Sister Size Chart below.
Amanté Bra Sister Size Chart

The chart takes away all confusion as you notice the on-size shifts in diagonal directions. As you can see in the chart above, a 32C can also be a 34B | 36C also works as a 32DD and vice versa.
Indivdiual Bra Sister Size Charts as per Band Size
32 Band Sister Size Chart
32 Band Size | ||
Current Bra Size | Sister Size Up | Sister Size Down |
32B | 34A | 30C |
32C | 34B | 30D |
32D | 34C | 30DD |
34 Band Sister Size Chart
34 Band Size | ||
Current Bra Size | Sister Size Up | Sister Size Down |
34B | 36A | 32C |
34C | 36B | 32D |
34D | 36C | 32DD |
34DD | 36D | 32DDD |
36 Band Sister Size Chart
36 Band Size | ||
Current Bra Size | Sister Size Up | Sister Size Down |
36B | 38A | 34C |
36C | 38B | 34D |
36D | 38C | 34DD |
36DD | 38D | 34F |
38 Band Sister Size Chart
38 Band Size | ||
Current Bra Size | Sister Size Up | Sister Size Down |
38C | 40B | 36DD |
38D | 40C | 36DD |
38DD | 40D | 36F |
40 Band Sister Size Chart
40 Band Size | ||
Current Bra Size | Sister Size Up | Sister Size Down |
40C | 42B | 38D |
40D | 42C | 38DD |
40DD | 42D | 38F |
40F | 42DD | 38DDD |
42 Band Sister Size Chart
42 Band Size | ||
Current Bra Size | Sister Size Up | Sister Size Down |
42C | 44B | 40D |
42D | 44C | 40DD |
42DD | 44D | 40DDD |
42F | 44DD | 40DDDD |
The next time your favorite brand runs out of a pretty design or your bra just doesn't feel right, you’ll know what to do. Also, remember to keep the amanté Bra Sister Size Chart handy as the sizes follow a global standard.
That said, even though sister sizing is usually accurate, there are chances that you may find exceptions. The best option to get the best fitting bra is to find your perfect fit.
FAQs
Do bra sister sizes work?
Yes, sister sizes often work. You can go up or down one size, to find your perfect fit.
What bras are sister sizes?
Sister sizes are a group of bra-sizes equivalents that are related by cup volume.
What is the sister size for DDD?
Sister size for DDD is F.
When you go up a band size do you go down a cup size?
Yes, that’s correct.
How do I know if I need a bigger cup or band?
You should go up the cup size if there’s spillage happening. If your cup fits well and the band is digging into your skin, then go one band size up.
Shop Bra by Sizes:
32B Size Bra | 32C Size Bra | 32D Size Bra | 34B Size Bra | 34C Size Bra | 34D Size Bra | 36B Size Bra | 36C Size Bra | 36D Size Bra | 38B Size Bra | 38C Size Bra | 38D Size Bra | 40C Size Bra | 40D Size Bra |
Check out our other blogs:
What is the Difference Between a Bra and a Bralette?Bras for Teenagers
Types of Bra
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