Wearing your newest and best fitting bra, not padded, place a tape measure around your rib cage just below the wire of your bra.
The tape should be level all the way around. Pulling the tape firmly measure in inches rounding up or down to the nearest inch.
If this number is an odd one add 5, if its an even one add 4. eg: measurement is 31 1/4 inches, your band size would be 36.
It is a common mistake to think that your actual under bust measurement in inches is your band size!
Next, place the tape around the fullest part of your bust again keeping the tape level. This should be neither a firm or loose measurement. Round the measurement to the nearest inch. The difference in the inches between the two then gives the cup size.
For example, a one inch difference would make you an A, two a B, three a C, four a D, five a DD, six an E and so on.
So if your back size is 34 inches and your bust size is 37 inches, that would make you a 34C.
Measuring is only a guide! If the bra you are wearing when taking the measurments is too small this can give a false size!
It is better to go to a shop to be measured and try on where possible!
How can you tell if you are wearing the wrong size bra?
There are many tell-tale signs that you are wearing the wrong size bra.