Sister Sizes Explained

What is a Sister Size?

Bra sizing is a kind of magic, where one bra size can have many Sister Sizes.

Sister sizes are groups of bra-size equivalents that are related by cup volume. Where your specific bra size might have a number or related sizes. This means that if you can't find your favourite style in your size, you might be able to choose your sister size.

How do you know, when to size up or size down for a sister size

You don't need to wait to use this trick to find a bra in a particular size - if your fave has sold out.

If you are happy with the cup size that you have and the way that it fits. But the band size feels a little firm - you can go up a back size to have a bit more room - and use the sister size to keep the same size cup! For example, if you fit a 12D in the cup- but feel like the band might be a bit too tight you could move up to a size 14C to get a bit more room in the band and keep the same cup.

Alternatively, if you feel like the band is a little loose but the cup fits, and you would like a more firm fit. Size down in the back, just remember to go up in the cup size to get the same size cup. For example if you are wearing a size 16C, but feel like the band is a little loose you can go down a back size to a 14 and up a cup size to a D cup.

Rule of Thumb

If you go up a band size, then you go down a cup size.

Or...

If you go up a cup size, then you go down a band size.

Sister Size Chart

Using the table below find your size - all sizes on the same row are your sister size. For example, a 12D has a sister size of a 10DD, 14C, 16B or 18A.

8A	10AA	-	-	-	-	-	-	-	-
8B	10A	12AA	-	-	-	-	-	-	-
8C	10B	12A	14AA	-	-	-	-	-	-
8D	10C	12B	14A	16AA	-	-	-	-	-
8DD	10D	12C	14B	16A	18AA	-	-	-	-
8E	10DD	12D	14C	16B	18A	-	-	-	-
8F	10E	12DD	14D	16C	18B	-	-	-	-
8FF	10F	12E	14DD	16D	18C	20B	-	-	-
8G	10FF	12F	14E	16DD	18D	20C	22B	-	-
8H	10G	12FF	14F	16E	18DD	20D	22C	-	-
8I	10H	12G	14FF	16F	18E	20DD	22D	24C	-
8J	10I	12H	14G	16FF	18F	20E	22DD	24D	-
-	10J	12I	14H	16G	18FF	20F	22E	24DD	26D
-	-	12J	14I	16H	18G	20FF	22F	24E	26DD
-	-	-	14J	16I	18H	20G	22F	24F	26E
-	-	-	-	16J	18I	20H	22G	24FF	26F
-	-	-	-	-	18J	20I	22H	24G	26FF
-	-	-	-	-	-	20J	22I	24H	26G

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Signs it’s time for a bra fitting

We recommend that you get fitted once every 12 months. However, if you notice your body is changing you should get professionally fitted, regardless of how recently you were fitted. A woman's body can change due to puberty, pregnancy and due to fluctuations in weight. Wearing the correct bra size promotes good breast health, it’s important to keep an eye on any changes in breast size.

Guide to buying her first bra

If you think it’s time to start shopping for your daughter's first bra, we’ve got you covered. We recommend popping into your local Bendon store for a professional fitting. If you’re interested in more information, check out our guide The First Bra for Beginners: How to buy your daughter her first bra.

What happens at a fitting

A bra fitting is a super quick way to find out your bra size. One of our lovely retail team members will measure you, have a quick chat about your favourite bra styles and then complete a fit check. If you want to know more about what happens at a bra fitting, check out our guide.