Key Facts
- Breasts come in all shapes and sizes.
- Although most lumps or changes in your breast are normal when you’re a teen, check with your HCP if you have a new lump.
- A well-fitting bra helps prevent discomfort in the breasts, back, and shoulders.
If you’re ready to buy your first bra or if your breast size has changed, you may be wondering what size bra to buy. Figuring out the correct size can be tricky unless you do your homework first and do it correctly. In fact, nearly 50% of people who wear bras are wearing the wrong size! But have no fear, this guide will help you measure yourself correctly to determine the size you will need (chest size and cup size). This will be important when buying a bra as well as other clothing that uses bra or cup measurements, such as bathing suits. However, you should always try on your bras first, especially since different brands and styles fit differently. If you are about to buy your first bra, it’s best to go to a department store that has a special section that sells bras and underwear, usually called the “lingerie department”. Ask to be fitted by a “lingerie specialist” (a professional who has special training in fitting bras). This service is free, and having the measurements done by a professional will make sure that your bra fits correctly. By doing this, you’ll find the bra that feels the best and also looks the best under your clothes.
If you would feel more comfortable figuring out your bra size at home, the following information will guide you through the steps of measuring yourself.
Band/Chest size:
Place a cloth measuring tape under your breasts, on your ribs. Wrap the tape around your chest so the tape measure meets the beginning part of the tape. Check the number (in inches) you have, then try to fit two fingers under it, if you can’t it’s too tight. If you can, it’s just right. Now, if the measurement is an odd number, try rounding it up to an even number. For example: if the measurement around your chest is: 35.2″, round up to 36” This means that your chest size is 36.
Cup size: Next, you will measure around your chest at the largest or fullest part of your breasts, called your “bust line.” You need to measure with your arms straight down, so ask someone you feel comfortable with to help you (like your mom, sister, or friend).
Your bust line measurement will be higher than your chest (“under the breast”) measurement. Your cup size is the difference between your chest size and your bust line measurement.
For example: Your bust line measurement at the fullest part of your bust is 34″ and your chest size is 32″. 36″ – 32″ = 4″. The difference is 2″, which means your cup size is a B cup.
Bra cup size:
| Cup Size: | Difference: |
| AA Cup | 0 inch |
| A Cup | 1 inch |
| B Cup | 2 inch |
| C Cup | 3 inch |
| D Cup | 4 inch |
| DD Cup | 5 inch |
| E Cup | 6 inch |
| F Cup | 7 inch |
| FF Cup | 8 inch |
| G Cup | 9 inch |
| GG Cup | 10 inch |
| H Cup | 11 inch |
| HH Cup | 12 inch |
| J Cup | 13 inch |
| JJ Cup | 12 inch |
| K Cup | 15 inch |
What should I know before I buy a bra?
A bra supports your breasts. While some people don’t wear one, others like to wear them, especially when they play sports or are active. All bras are shaped to fit around both your chest and your breasts.
Some bras are sized small, medium, large, x-large, xx-large, or xxx-large. Bras sized this way, such as sports bras, fit snugly but should be comfortable. Sports bras also now come in cup sizes for a more supported fit, but again you should measure yourself based on the brand’s size chart. A well-fitting sports bra can prevent breast pain during sports or running.
Fitted bras have both a breast cup size and chest size. The cup sizes range most commonly from AA to K, and the chest sizes (aka band size) commonly range from about 28 inches to 52 inches (this is the number of inches around your chest at the fullest part of your bust). It is important to mention that cup and chest sizes do range beyond a K cup and greater than 52 inches. However, not all stores will carry a wide range of sizes, so it is a good idea to check out a few stores or shop online to find the size that fits you the best. You or a clerk at the store can measure you for the right size bra. You should try on many bras to find the most comfortable size and style. Finding a well-fitting bra is important to prevent breast discomfort, back pain, and shoulder pain. Finally, it’s important to get measured every couple of years, because our bodies change for lots of different reasons and so can our bra size! Getting into the habit of annual or biannual fittings can save you from wearing an improper-fitting bra!
Our health guides are developed through a systematic, rigorous process to ensure accuracy, reliability, and trustworthiness. Written and reviewed by experienced healthcare clinicians from Boston Children's Hospital, a Harvard Medical School teaching hospital and consistently ranked as a top hospital by Newsweek and U.S. News & World Report, these guides combine clinical expertise, specialized knowledge, and evidence-based medicine. We also incorporate research and best practices from authoritative sources such as the CDC, NIH, PubMed, top medical journals, and UpToDate.com. Clinical specialists and subject matter experts review and edit each guide, reinforcing our commitment to high-quality, factual, scientifically accurate health information for young people.