Brassiere measurements

Brassiere sizes are commonly labeled by manufacturers with a code consisting of a number and one or more Latin capital letters. Several different systems are used worldwide to define these labels, based on either inch or centimetre body measurements.

Sizing varies considerably between garments produced by different manufacturers; even professional bra fitters often produce inconsistent results. There is currently no commonly agreed formal standard that defines an inch-based bra-size system. Due to these uncertainties in labeling, customers should always verify whether the garment fits well, rather than rely entirely on the labeled bra size. The method described below attempts to approximate current practice in the United States and United Kingdom.  All measurements are in inches.

• First measure tightly around the torso, directly underneath the breasts. This is the frame size, or underband.
• To calculate the band size, add 5 in if the frame size is an odd number, or 4 in if it is even (bras are generally available in band sizes separated by two inches, all labeled by an even number).
• Next measure loosely around the chest including the fullest part of the breasts, while standing straight with arms to the side. This is the bust size or overbust.
• The cup size is then the difference between the bust size and the underband size, converted into a letter using the following table:

Difference between bust size and underbust size (inches)	Cup size (UK and Australia)	Cup size (rest of Europe and US)
Less than one inch	AA	AA
2 inches	A	A
3 inches	B	B
4 inches	C	C
5 inches	D	D
6 inches	DD	E or DD
7 inches	E	F or DDD
8 inches	F	G
9 inches	FF	H
10 inches	G	I
11 inches	GG	J
12 inches	H	K
13 inches	HH	L
14 inches	J
15 inches	JJ

The actual volume of the bra cup depends not only on the cup size calculated as above, but also increases with the band size. In fact, most bra manufacturers use the same cup volume for bras which are related by an increase in cup size and a decrease in band size. For instance, the cup volume is the same for 30D, 32C, 34B, 36A, etc. It is for this reason that bra sizes have "sister sizes" which are related in this way by having the same cup volume (e.g. 32C and 34B). Although it is important that a wearer has a correctly fitting bra, it is sometimes possible that two adjacent sister sizes fit equally well, since the cups are the same size, and the difference in band size can be accommodated by fastening the back strap on a different hook.

Variations

The above method is common, though certainly not universal, and is recommended by many manufacturers. In the United States, various manufacturers and boutiques recommend adding different numbers to the measured circumference to determine band size, generally from 4 to 6 inches. A further complication is that some manufacturers say that when the under-the-bust measurement is 35 in (89 cm) or more, only 3 in (7.5 cm) should be added to determine the band size. Still others, particularly stores that specialize in specialty sizes, do not recommend adding anything to the size, as the band is meant to fit around the area measured, not higher.

Most countries (in particular most of Asia and Europe) use centimetres rather than inches. In Australia and New Zealand dress size is commonly used instead of band size.

New European system

The European dress-size standard EN 13402 defines bra sizes based on the following two body dimensions (measured in centimetres):

bust girth maximum horizontal girth measured during normal breathing with the subject standing erect and the tape-measure passed horizontally, under the armpits (axillae), and across the bust prominence (preferably measured with moderate tension over a brassiere that shall not deform the breast in an unnatural way and shall not displace its volume)

underbust girth horizontal girth of the body measured just below the breasts

Bras are labeled with the underbust girth (rounded to the nearest multiple of 5 cm), followed by a letter code that indicates the cup size = bust girth − underbust girth

according to this table defined by the standard:

Code	AA	A	B	C	D	E	F	G
Cup size [cm]	10–12	12–14	14–16	16–18	18–20	20–22	22–24	24–26

Example: A woman with underbust girth 89 cm and bust girth 104 cm has cup size 15 cm (= 104 cm – 89 cm) or "B". Her underbust girth rounded to the nearest multiple of 5 cm is 90 cm. Therefore, her bra size according to the new standard is 90B.

Older European systems

The EN 13402 standard is (as of 2006) still relatively new, and a range of other cup-size definitions are also currently used by European vendors, using either centimeters or inches to indicate the underbust girth.

One common cup size system amongst European manufacturers, in order of increasing size, is: AAA-AA-A-B-C-D-DD-E-F-FF-G-GG-H-J, although the use of double letters is not consistent between manufacturers (e.g. some may use EE rather than F, DDD rather than E, etc.). The majority of bra bands run true to size (as in, a size 36 band measures, when stretched, 36 inches). It is expected that the EN 13402 standard will eventually help resolve the current confusion surrounding cup-size codes in Europe.

Table

Region	Sizes
	XS		S		M		L		XL		XXL
EU and Japan	60–65	65–70	70–75	75–80	80–85	85–90	90–95	95–100	100–105	105–110	110–115	115–120
USA and UK	30	32	34	36	38	40	42	44	46	48	50	52
France and Spain	75–80	80–85	85–90	90–95	95–100	100–105	105–110	110–115	115–120	120–125	125–130	130–135
Italy	70	75	80	85	90	95	100	105	110	115	120	125
Sports bra	1	2	3	4	5	6	7	8	9	10	11	12
Australia/New Zealand	6	6	8	8	10	10	12	12	14	14	16	16