Determining Correct Bra & Cup Size
If you prefer to do it out by hand, read and follow the instructions below. You will need a tape measure (preferably paper) in inches, and a pencil. (Optimally, you should be wearing your most comfortable bra when the following measurements are done, though this is not mandatory.)
There are 2 variables we need to determine to correctly find your bra and cup size. These variables are your frame size and your chest+breast size. Keep in mind, however, that determining your bra and cup size is no an exact science. If you find you should be wearing a 34 C, but a 32 B fits you better, obviously get the more comfortable one!
1. Determine Frame & Bra Size
The frame size is the diameter around your chest JUST BELOW your breasts. Using the tape measure, measure around your ribcage directly under your breasts. There should be no breast tissue measured while determining your frame size.
To determine the bra size, add 5 to this number. If the number you get is odd, round up to the next even number. For example, if your frame size is 26 inches, when you add 5 to this you get 31 inches. You should therefore round up to the even number which is 32 inches (since bras only come in even numbers). This is your bra size, 32 inches.
2. Determine Breast Size
The next measurement goes around the chest over and including the fullest part of your bust (usually at the level of the nipples). Technically, you should take this measurement while wearing a comfortable bra. This is the diameter of your chest+breast. Record this number on the form.
3. Calculate Cup Size
Now, take the chest + breast size number, and subtract your bra size number. Then use the table below to determine your cup size.
| 0 to 1/2 inch | |
| 1/2 to 1 inch | |
| 1 to 2 1/2 inches | |
| 2 1/2 to 3 1/2 inches | |
| 3 1/2 to 4 1/2 inches | |
| 4 1/2 to 6 inches | |
| 6 to 7 inches | |
| 7 to 8 inches | |
| etc., etc. |
4. Example
Let’s assume your frame size is 31 inches, your bra size is therefore 36 inches (31 + 5 = 36 inches). In addition, assume you measured your chest+breast size at 40 inches. Now, take your chest+breast size (40), and subtract your bra size (36). You get 4 inches as the difference. Using the table above, you find that anyone with a difference between 3 1/2 to 4 1/2 inches (including 4) has a cup size D. Your correct bra and cup size is therefore 36 D.
