We use the traditional plus four or five inches system. A lot of fuller bust companies add no inches or 2 inches only rather than the plus four or five. This is really a matter of preference of the company making the product as the actual physical size of the bra will be the same just the size it is called will vary. So for example someone who is a 30H in a brand that uses the newer system would be a 34F in our system. However the actual bras would be similarly proportioned and it is not that you are truly one size or the other.

Neither system is right or wrong but as a customer it is key to know what system the company you are buying from is using so that you get a bra that physically fits you.

Sister size is a size where the cup volume stays the same despite the band and cup number changing – this is why if for example your bra size is 34C but it is out of stock you could try a 32D or 36B as the cup is made from the same size patterns pieces and uses the same size bra wires – it is just the band which is a different length. As the bra will have 3 rows of hooks and eyes on the end of the band it can often work on the tightest if you size up or on the loosest or with a bra extender if you size down. Use this handy chart to find your two sister sizes.
We recommend you don't go up or down more than one either side though as then the band would be to tight or loose