Sister sizing is a clever tool to use when a bra is unavailable in your size, or you prefer a slightly looser or tighter fit in the band of your bra.
For example, if you usually wear a 14C you could also try the 12D, which has the same cup volume but a smaller band size. Use the following table to find your sister size - read:
Note: while sister sizing is a clever trick that we wish we had learnt earlier in life, it's not a perfect solution, and we recommend trying different sizes to find the most comfortable and supportive fit. Additionally, it's important to keep in mind that different brands and styles of bras may fit differently, so you may need to try different sizes and styles within a brand to find the best fit.
Let us know if you have a question about sister sizing.