Nursing Bra -

What size Do I need?


Fitting a bra is much more of an art than a science. Bosom Buddies has fit thousands of bras over the years in our retail stores. While there are guidelines to help you get started, the best method is trial and error. We’ve found that even if you know your bra size, you may be that size in one brand or style and a different size in another.

There are two factors to help you determine which size bra to start with: measuring and looking at the bra you are wearing now (even if it is uncomfortable).


Though manufacturers differ in their recommendations, there are two basic measurements used to determine a possible bra size.

First, put on your best fitting bra. During pregnancy and lactation, when breast size is changing, this can be a challenge. But, do your best.

Then, with a cloth tape measure, measure around your body just under your arms. This will be above the widest part of your bust. After you have the tape measure in place, take a deep breath and relax. The tape should be snug, but not tight around you. Record this measurement. If it is a fraction or an odd number, round up to the next whole even number. This is your approximate band size.

Next move the tape measure down to the widest part of your bust (usually right at the level of your nipples). Be sure the tape measure is parallel with the floor around your back. Again, the tape measure should be snug, but not tight. Record this measurement. Subtract your measured band size from this number.

If the difference between the numbers is:Try cup size:
less than 1"
1" to 2"
2" to 3"
3" to 4"
4" to 5"
5" to 6"
6" to 7"
7" to 8"
8" to 9"
9" to 10"
over 10"

Your current bra:

Before deciding which size bra to try first, also consider your current bra. If you are comfortable in it, that is probably the best size in which to order another bra.

  • If the band is tight, go up one band size.
  • If you can hardly get it on, go up two band sizes.
  • If the cups feel snug, go up one cup size.
  • If you are spilling out of the cups, go up two cup sizes.

Also consider the stage of pregnancy or lactation you are in when determining how your current bra fits.

  • If you are in the beginning stages of pregnancy, add one cup and band size to the recommendations above to allow for growth. Also consider that you may have to buy more bras later in your pregnancy as your body changes.
  • If you are in late pregnancy or have just given birth in the last 2-3 days (before your milk comes in), add one cup size to the recommendations above to allow for growth.

What if:

  • My band is riding up in the back?
    Generally that means you need a larger cup size. Try this, even before going down in the band size.
  • My cups are puckering (too big)?
    If you are pregnant, this may be the right size after baby comes. If you are getting some support from the bra now, this is probably a good size.
  • The cups are huge!
    Go down a cup size. Breast size tends to grow in last pregnancy and when your milk comes in, but not much after that.
  • The underwire in my bra is rubbing under my arm.
    Try a smaller cup size (but be sure the wire still surround as breast tissue and does not lie across it), a smaller band size, or a different style. For some moms, they find an underwire just doesn’t work at this point in their lives, because in order to get a wide enough wire to surround all breast tissue, the wire is too big and ends up rubbing under the arms.

What size do I get?

Look at your current bra size and how it fits and compare that with your measurements. If they are the same, order bras in that size. If the measurements and your current bra size and fit indicate very different sizes, you’ll have to do more trial and error to determine which bra is right. Err on the larger size, and rely more heavily on your bra size than the measurements.

Also remember that different manufacturers and styles will fit differently. Look at bras a cup and band size bigger and smaller than you think you need. In the descriptions, we have indicated where bras tend to run big or small.