How to calculate the sister size?
You can either go for ‘SISTER DOWNSIZE’ or ‘SISTER UP SIZE’ depending on your whether you need bigger or shorter band size.
SISTER DOWNSIZE: If you want smaller sister size of your bra size, you need to go down one size on your band size and one size up on cup size. (For instance, if your bra size is 34B, you SISTER DOWNSIZE would be 32C.
SISTER UP SIZE: If you want bigger sister size of your bra size, you need to go up one size on your band size and one size down on cup size. (For instance, if your bra size is 34B, you SISTER UP SIZE would be 36A.
Below chart displays the sister sizes in cells with similar colors,
If your bra size is 32C, 34B is nothing but a sister size where the cup remains the same size but band size is more.