Breast Health: Buying a Bra

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 breast discomfort, back pain, and shoulder pain.


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. 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. Of course, trying on bras is always important, 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 decide you would feel more comfortable figuring out your bra size at home, the following information will guide you through the steps of measuring yourself.

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. When you have the measurement number, add 5 inches.

For example: if the measurement around your chest is: 27″.

27″ + 5″ = 32″

This means that your chest size is 32.

If your measurement ends up to be an ODD number, you will need to go up to the next EVEN number to figure out your size.

For example: your measurement around your chest is: 28″.

28″ + 5″ = 33″

This means that your chest size is 34.

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″. 34″ – 32″ = 2″. The difference is 2″, which means your cup size is a B cup.

Bra cup size:

Cup Size: Difference:
AA Cup ½ inch
A Cup 1 inch
B Cup 2 inch
C Cup 3 inch
D Cup 4 inch

What should I know before I buy a bra?

A bra supports your breasts. While some girls don’t wear one, others like to wear them, especially when they play sports. All bras are shaped to fit around both your chest and your breasts.

Some bras are sized small, medium, or large. Bras sized this way, such as sports bras, fit snugly but comfortably. 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 from AA (smallest) to H (largest), and the chest sizes range from about 30 inches to 40 inches (this is the number of inches around your chest at the fullest part of your bust). Not all stores will carry very small or very large sizes, so you may have 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.