What Size Bra Should I Buy?

Like a pair of jeans, every bra fits slightly differently and not every bra will suit every bust shape, so it’s great to try a few styles of nursing bra to make sure you get the support you deserve. Below are some steps on how to fit your bra correctly…

There’s a few different types of terminology when talking about nursing bras, and a few key points to help you assess if you have the right fit.   Not all bras are the same size and shape, and there can be variation in how it feels on your body.   Remember that we have a no-fuss exchange policy at Breastmates, so you are welcome to purchase and try on several styles at home, then return whichever doesn’t fit.     And if you are still confused, we’re always available to help you.

Side Sling

When a nursing bra is referred to as having a “Side Sling” it means the inner support sits on the outer sides of your breasts, underneath and around the sides (but not across the top).

Check the side sling is sitting comfortably, and doesn’t dig into your skin or sit too high under your arm.     Check that the sling doesn’t cover or obstruct your areola or nipple.


When a nursing bra is referred to as having an “A-frame” this refers to the shape of the support around your breast when the nursing bra is open.   The A-frame is an inside layer that sits around your breast, it goes around the sides, underneath, and across the top.    An A-frame support is typically used in fuller figure bra design, and usually women feel great support when wearing.    Check the A-frame is sitting comfortably against the breast and that it doesn’t cut in across the top of the cup.    Check the inside opening is large enough to expand and doesn’t cut in.     Make sure there is enough overlap between the top of the cup and the a-frame shape.  If there is a gap this may mean the cup is too small and your breast is pushing the cup out and putting strain on the cup.




Practise opening and closing the nursing clips on your new bra.  Check the cup drops down far enough for feeding, ideally the cup should sit lower than the A-frame at the centre so it drops down further.    If the bra has either an A-frame or a side sling support panel, make sure it doesn’t cut in anywhere over the breast or at the underarm when the cup is dropped down.


The straps should rest comfortably on your shoulders.    They should feel supportive and not dig-in or leave red marks.


The back band should run parallel with the ground, and sit firmly but comfortably around your back.   If you’re in the later stages of pregnancy, ensure you have enough room/hooks to tighten the band once baby is born.



The cup of your new bra should sit comfortably over the breast, and provide good coverage without any wrinkling or bulging over the edge.   If you’re pregnant, make sure that you can slip one flat hand into the top cup for when your milk comes in.


This article was written with assistance & images from our nursing bra supplier: Hotmilk