My size scale may differ from other sellers. That’s why, in order to ensure a perfect fit, the most important information for me is your measurements.
It will be the best if you provide the following measurements in the "Note to Seller" at checkout:
For GARTER BELTS
- waist circumference
- waist and hips circumference
- bust and underbust circumference
You can calculate your bra-band size and your cup size by measuring around the rib cage and full bust, wearing your best-fitting bra. (Large-busted women especially need support for accurate measurements.)
Using a full-length mirror, measure around the rib cage, making sure the tape is level around the body and pulling it snug. To this measurement, add either 4 or 5 in. to get an even number. Example: if the snug rib cage is 29 in., add 5 for a total of 34 in. This is the bra-band size.
Next, measure the bust around the fullest part, again keeping the tape level, but this time don't pull it snug. To determine the cup size, subtract the bra-band size from the full-bust measurement. The difference, in inches, tells you the cup size: 1 in. for A, 2 for B, 3 for C, 4 for D, 5 for DD (or E), 6 for DDD (or F), and 7 in. for FF. For example, if your bra band is 36 in. and the full bust 38 in., the cup size is B; you'll make a size 36B.
(taken from http://www.threadsmagazine.com)
Coco'sRetroCloset Sizng Chart for garter belts and girdles