Why we need to add 5 to the rib cage size to getting the bra size?

Question

My size around the rib cage is 29. Biut my bra size is 34 .Why do we add 5 to the rib cage size to get bra size?

Answer 1

Actually the difference in the under breast and over breast dimension is used to determine the cup size. Since you have a difference of 5 inches, you subtract 2 leaving 3 which would make you a 29C. Fitting for a bra requires one to take the measurement arround the fullest part of the bust and subtract the measurement arround the rib cage. The difference in the two will tell you which cup size you need. It works like this:

difference= cup size

3" A
4" B
5" C
6" D
7" E or DD depending on what country you're in
8" F

This will give you a place to start but different makers and styles may require a little adjustment to find a good fit. But remember, the number you use should be the smaller of the two not the larger. You may need someone else to help you take these measurements correctly.

Answer 2

What? I've never heard a bra measured like that & I've worn one for almost 30 years! You should measure around your chest just under your breasts--that is the size of your bra--now for cup size, you need to measure around your body at the fullest part of your breasts. The difference between the chest measurements and the across the breast measurements will tell you the cup size--if there's 5 inches difference, I'd say you are in a C-cup. The easiest way to do this if you don't want to spend all day with a measuring tape is to just go try on the size you think you need--if it fits, you've got it, if it doesn't--bulging out of it, or it pinching you anywhere, you need a larger one; bra is baggy and doesn't give any support, you need a smaller one.

Answer 3

to account for the breasts I suppose