Measuring for a bra can be confusing. There are two steps involved and they are:
How To Measure Bra Cup Size
Measure around your chest, just below your breasts.
Add 5 inches if it is an odd number.
Add 4 inches if it is an even number.
To find out what cup you need, measure around the fullest part of your breasts.
If the two numbers are the same, you need an AA-cup.
If the two numbers differ by 1 inch, you need an A-cup.
If the two numbers differ by 2 inches, you need a B-cup.
If the two numbers differ by 3 inches, you need a C-cup.
If the two numbers differ by 4 inches, you need a D-cup.
Remember this is just a guide. You really need to try bras on and find the one that fits best. When buying a new bra make sure it hooks comfortably on the last hook so that as it stretches you will still be able to hook it. Buy one bra and wear it to be sure that the bra is right for you.
Hope this is helpful
