Even though they are essential to most women, the fact is that shopping for a bra is a tedious task. This is further complicated because the cup size is not the only thing women need to worry about. They also have to worry about the fit of the bra, the circumference, and how much of a lift the bra gives your breasts. Determining them all can be a difficult task, but it becomes even more difficult when you realise one standard bra cup may not fit every one of the same sizes because breast volume differs for every woman. In fact, a woman’s breast volume plays a huge role in how well or snugly the bra fits.
Unfortunately, bra manufacturers don’t take breast volume into consideration when making bras, and nor produce them in standard sizes in reality.
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What are the different bra cup sizes?
Bra sizes are also known as bust sizes and aim to give you information about the circumference of the bra and the cup size. The number on the tag refers to the circumference, while the letters refer to the cup size.
However, this sizing changes from brand to brand, and it is also subject to change based on the country you are in. Furthermore, each brand has a standard sizing chart that they follow. The different bra cup sizes usually available on the market, regardless of the brand are AA, A, B, C, D, DD, and E. There are further categories; however, these are the ones that are most commonly sold.
The problem that occurs with this cup sizing is that two women wearing a C cup size may not have the same breast volume and hence, may not have the same fit for the bra. Standardising this bra cup size does more harm to the breast structure and laxity than good, as most women wear a bra size that is not the right fit for their breasts.
What is meant by breast volume?
Breasts are made up of both glandular and fatty tissue, with the size of the breasts depending on the content of the latter.
The volume of breast tissue refers to the volume of fat and this helps determine the size of the bra as well. Breast volume can vary significantly amongst the people who wear the same cup size, and this has been proven in multiple different types of research.
Below, is an example of this; the research was performed on breast volumes of women and the incidence of breast cancer. According to this study, the breast volume amongst those wearing the B cup size bras was as follows:
| Rib cage circumference (cm) | Median (range) (mL) |
| 70 | 350 |
| 75 | 350 (150–750) |
| 80 | 350 (150–650) |
| 85 | 500 (200–1100) |
| 90 | 600 (500–800) |
| 95 | 650 (400–800) |
| 100 | 850 (800–900) |
| 105 | 700 |
Clearly, breast volumes can vary significantly amongst the same bra cup sizes.
Why is Breast volume important?
Breast volume is not only important for finding the right bra size but also in the field of plastic and cosmetic surgery. Breast volume is also important if you are thinking of getting breast implants. Most people choose to undergo breast augmentation procedures to increase the size of their breasts. In fact, many patients often specify a cup size they want to be, for example, 14DD or 10C.
Since the standardisation of cup size is in reality not so standard, this is not an accurate way to choose what size you want to be. In fact, it could mean quite a few different sizes. Therefore, it is important to know what breast volume you are aiming for. This also helps plastic surgeons achieve the results their patients actually want.
Furthermore, it should be noted that the cup sizes differ per country and brand. With this in mind, the following chart has been designed to help you assess the difference in breast volumes and bra cup sizes.
Comparison of bra sizes and breast volumes in different countries
| Underwire size | Bra size (US system) | Bra size (Aus/UK system) | Cup diameter | The volume of one cup | Weight of both breasts |
| 30 | 32A 30B 28C | 32A 30B 28C | 9.7 cm (3+5⁄6 in) | 240 cm3 (15 cu in) | 0.43 kg (0.95 lb) |
| 32 | 34A 32B 30C 28D | 34A 32B 30C 28D | 10.6 cm (4+1⁄6 in) | 310 cm3 (19 cu in) | 0.56 kg (1.2 lb) |
| 34 | 36A 34B 32C 30D 28E | 36A 34B 32C 30D 28DD | 11.4 cm (4+1⁄2 in) | 390 cm3 (24 cu in) | 0.70 kg (1.5 lb) |
| 36 | 38A 36B 34C 32D 30E 28F | 38A 36B 34C 32D 30DD 28E | 12.3 cm (4+5⁄6 in) | 480 cm3 (29 cu in) | 0.86 kg (1.9 lb) |
| 38 | 40A 38B 36C 34D 32E 30F 28G | 40A 38B 36C 34D 32DD 30E 28F | 13.1 cm (5+1⁄6 in) | 590 cm3 (36 cu in) | 1.1 kg (2.4 lb) |
| 40 | 42A 40B 38C 36D 34E 32F 30G 28H | 42A 40B 38C 36D 34DD 32E 30F 28FF | 14.0 cm (5+1⁄2 in) | 710 cm3 (43 cu in) | 1.3 kg (2.9 lb) |
| 42 | 44A 42B 40C 38D 36E 34F 32G 30H 28I | 44A 42B 40C 38D 36DD 34E 32F 30FF 28G | 14.8 cm (5+5⁄6 in) | 850 cm3 (52 cu in) | 1.5 kg (3.3 lb) |
| 44 | 44B 42C 40D 38E 36F 34G 32H 30I 28J | 44B 42C 40D 38DD 36E 34F 32FF 30G 28GG | 15.7 cm (6+1⁄6 in) | 1,000 cm3 (61 cu in) | 1.8 kg (4.0 lb) |
| 46 | 44C 42D 40E 38F 36G 34H 32I 30J 28K | 44C 42D 40DD 38E 36F 34FF,32G 30GG 28H | 16.5 cm (6+1⁄2 in) | 1,180 cm3 (72 cu in) | 2.1 kg (4.6 lb) |
| 48 | 44D 42E 40F 38G 36H 34I 32J 30K 28L | 44D 42DD 40E 38F 36FF 34G 32GG 30H 28HH | 17.4 cm (6+5⁄6 in) | 1,370 cm3 (84 cu in) | 2.5 kg (5.5 lb) |
| 50 | 44E 42F 40G 38H 36I 34J 32K 30L 28M | 44DD 42E 40F 38FF 36G 34GG 32H 30HH 28J | 18.2 cm (7+1⁄6 in) | 1,580 cm3 (96 cu in) | 2.8 kg (6.2 lb) |
| 52 | 44F 42G 40H 38I 36J 34K 32L 30M 28N | 44E 42F 40FF 38G 36GG 34H 32HH 30J 28JJ | 19.0 cm (7+1⁄2 in) | 1,810 cm3 (110 cu in) | 3.3 kg (7.3 lb) |
| 54 | 44G 42H 40I 38J 36K 34L 32M 30N 28O | 44F 42FF 40G 38GG 36H 34HH 32J 30JJ 28K | 19.9 cm (7+5⁄6 in) | 2,060 cm3 (126 cu in) | 3.7 kg (8.2 lb) |
| 56 | 44H 42I 40J 38K 36L 34M 32N 30O 28P | 44FF 42G 40GG 38H 36HH 34J 32JJ 30K 28KK | 20.7 cm (8+1⁄6 in) | 2,340 cm3 (143 cu in) | 4.2 kg (9.3 lb) |
| 58 | 44I 42J 40K 38L 36M 34N 32O 30P | 44G 42GG 40H 38HH 36J 34JJ 32K 30KK | 21.6 cm (8+1⁄2 in) | 2,640 cm3 (161 cu in) | 4.8 kg (11 lb) |
| 60 | 44J 42K 40L 38M 36N 34O 32P | 44GG 42H 40HH 38J, 36JJ 34K 32KK | 22.4 cm (8+5⁄6 in) | 3,000 cm3 (180 cu in) | 5.3 kg (12 lb) |
Breast volume comparison chart in different countries
How to find the best-fitting bra?
There are specific tips and tricks to finding a bra that fits you right. It is important to ensure that it meets the following;
- Firstly, the bra band should not ride up in the back or hang too low in the front. It should be held horizontally when viewed from the side and should fit firmly.
- Secondly, the underwire of your breast should be flat against the sternum, not digging into the chest. It should also be comfortable and hold your breasts up along the inframammary fold.
- Thirdly, your entire breasts should be covered by the bra cup, and the edge of the cup should not dig into your breasts. Furthermore, the top of your breasts should not be uncovered or bulging out of the bra cup, even with low-cut bras, and the topmost end of the cup should form a smooth line with no space between it and the breast. The center of the cup should lie over the nipple.
- Next, we move on to the bra straps. They should not be digging into your shoulder, or leave marks and cause irritation when you wear the bra. Moreover, it should not fall off your shoulder. If it does, it’s a sign the bra is too big and not a well-fitted bra.
- Both the support and lift your breasts get should come from the band around the rib cage and not the shoulder straps. Unfortunately, if the breast is not correctly supported, it can lead to neck and shoulder pain.
- Lastly, you should be able to breathe and move about easily in your bra, and there should not be any restrictions around your shoulders, chest, and/or neck.
Determining your size
If you are having a difficult time finding a bra size that fits you well, due to differences in breast volume or other issues with the standard size, you can opt for a method tried by plastic surgeons to find your bra cup size.
Before you can determine the bra cup size, you have to measure your rib cage circumference where the breasts end, from where your nipple is placed, and right where the breasts start. Based on the sizes you measured, the following cup sizes can be determined for you;
| Measurement | Measurement | Cup size |
| (inch) | (cm) | |
| 7.0 | 17.8 | A |
| 7.5 | 19.1 | A |
| 8.0 | 20.3 | B |
| 8.5 | 21.6 | B |
| 9.0 | 22.9 | C |
| 9.5 | 24.1 | C |
| 10.0 | 25.4 | D |
| 10.5 | 26.7 | D |
| 11.0 | 27.9 | DD |
The repetition of certain cup sizes with different measurements just goes to show how much of a variance there is between not only the breast volume and size but also the weight of the women wearing the same bra cup size. So, it’s important you take your rib circumference, breast size, breast weight, and volume into consideration in order to find the perfect fit for you.
Frequently Asked Questions about Bra Cup Sizes and Volume
How big is a DD cup in inches?
Generally, the DD cup is around 11 inches or 27.9 cm in size.
Is 38D a large or an XL for sports bra size?
When buying a sports bra, following the traditional bra size is not helpful at all. In fact, you need to be able to convert the sizes into letter sizes, ranging from XS to XXL. For example, 38D, 38DD, and 38E fall under the XL sizing of sports bras.
What’s the difference between A and AA bra cup sizes?
An AA cup is usually smaller than an A cup by approximately an inch or 2cm. It can change based on the brand you buy but AA cup size is the smallest cup size available.
What is an F-cup size and how much does an F-size breast weigh?
F cup size is one of the bigger sizes, with each breast weighing 1.2 kg, on average.
F-size breasts can be quite painful for women and often result in either chronic neck, shoulder, and back pain or a combination.
Medical References
- Ling Zhang, Eonyou Shin, Chanmi Hwang, Fatma Baytar. (2017) The use of 3D body scanning technology to assess the effectiveness of shapewear: changes in body shape and attractiveness. International Journal of Fashion Design, Technology and Education 10:2, pages 190-199.
- J. White, J. Scurr. (2012) Evaluation of professional bra fitting criteria for bra selection and fitting in the UK. Ergonomics 55:6, pages 704-711.
- N. Luk, W. Yu. 2016. Bra fitting assessment and alteration. Advances in Women’s Intimate Apparel Technology pages 109-133.
